I'm am going to just give the example xml package that just has the weight field added at this point then. Due note that this is not add the weight from the RTShipping.PackageExtraWeight appconfig. Here is the example code:
C#/VB.NET Code:
<?xml version="1.0" encoding="utf-8" ?>
<!-- ###################################################################################################### -->
<!-- Copyright AspDotNetStorefront.com, 1995-2011. All Rights Reserved. -->
<!-- http://www.aspdotnetstorefront.com -->
<!-- For details on this license please visit the product homepage at the URL above. -->
<!-- THE ABOVE NOTICE MUST REMAIN INTACT. -->
<!-- ###################################################################################################### -->
<package displayname="Google Base RSS 2.0 Feed" version="2.1" debug="false" includeentityhelper="false">
<query name="Products" rowElementName="Product">
<sql>
<![CDATA[
SELECT temp.*
FROM
(
select p.productid, p.name, isnull(pv.name, '') VariantName, p.description, p.sename, p.ImageFileNameOverride, p.SKU, isnull(p.FroogleDescription, '') ProductFroogleDescription, p.SEKeywords,
p.ManufacturerPartNumber, pv.price, isnull(pv.saleprice, 0) saleprice, isnull(pv.FroogleDescription, '') VariantFroogleDescription, isnull(pv.description, '') VariantDescr, pv.Condition,
ROW_NUMBER() OVER (ORDER BY p.productid) AS ROW, pv.Weight
from dbo.product p
join dbo.productvariant pv on p.productid = pv.productid
left join (select variantid, sum(quan) inventory from dbo.inventory group by variantid) i on pv.variantid = i.variantid
where p.IsSystem=0
and p.deleted = 0
and p.published = 1
and p.ExcludeFromPriceFeeds = 0
and pv.isdefault = 1
and case p.TrackInventoryBySizeAndColor when 1 then isnull(i.inventory, 0) else pv.inventory end >= @HideProductsWithLessThanThisInventoryLevel
) AS temp
WHERE temp.ROW >= @LowerBound AND temp.ROW <= @UpperBound and ProductID IN (SELECT DISTINCT ProductID from ProductStore WHERE StoreID = @SID)
]]>
</sql>
<queryparam paramname="@HideProductsWithLessThanThisInventoryLevel" paramtype="appconfig" requestparamname="HideProductsWithLessThanThisInventoryLevel" sqlDataType="int" defvalue="0" validationpattern="" />
<queryparam paramname="@LowerBound" paramtype="runtime" requestparamname="LowerBound" sqlDataType="int" defvalue="0" validationpattern="" />
<queryparam paramname="@UpperBound" paramtype="runtime" requestparamname="UpperBound" sqlDataType="int" defvalue="0" validationpattern="" />
<queryparam paramname="@SID" paramtype="runtime" requestparamname="SID" sqlDataType="int" defvalue="2" validationpattern="" />
</query>
<query name="StoreSite" rowElementName="Store">
<sql>
<![CDATA[
SELECT TOP 1 * FROM Store WHERE StoreID = @SID
]]>
</sql>
<queryparam paramname="@SID" paramtype="runtime" requestparamname="SID" sqlDataType="int" defvalue="2" validationpattern="" />
</query>
<PackageTransform>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:aspdnsf="urn:aspdnsf" xmlns:g="http://base.google.com/ns/1.0" exclude-result-prefixes="aspdnsf">
<xsl:output method="xml" omit-xml-declaration="no" encoding="utf-8" indent="no" />
<xsl:param name="EntityName">
<xsl:value-of select="/root/QueryString/entity" />
</xsl:param>
<xsl:param name="ShowInGrid">true</xsl:param>
<xsl:param name="GridCols">4</xsl:param>
<xsl:param name="UseDescr" select="aspdnsf:AppConfig(@SID, 'Froogle_UseDescriptionsIfFroogleDescEmpty')" />
<xsl:param name="LocaleSetting" select="/root/Runtime/LocaleSetting" />
<xsl:param name="WebConfigLocaleSetting" select="/root/Runtime/WebConfigLocaleSetting" />
<xsl:template match="/">
<rss version="2.0">
<channel>
<title>
<xsl:value-of select="/root/StoreSite/Store/Name" />
</title>
<link>
<xsl:value-of select="/root/StoreSite/Store/ProductionURI"/>
</link>
<description>
<xsl:value-of select="aspdnsf:AppConfig(@SID, 'RSSChannelDescr')" />
</description>
<language>
<xsl:value-of select="$WebConfigLocaleSetting" />
</language>
<pubDate>
<xsl:value-of select="/root/System/CurrentDateTime" />
</pubDate>
<lastBuildDate>
<xsl:value-of select="/root/System/CurrentDateTime" />
</lastBuildDate>
<xsl:apply-templates select="/root/Products/Product" />
</channel>
</rss>
</xsl:template>
<xsl:template match="Product">
<xsl:param name="ProductName" select="aspdnsf:GetMLValue(name)"></xsl:param>
<xsl:param name="ProductVariantName" select="aspdnsf:GetMLValue(VariantName)"></xsl:param>
<xsl:param name="ProductDescr" select="aspdnsf:GetMLValue(description)"></xsl:param>
<xsl:param name="VariantDescr" select="aspdnsf:GetMLValue(VariantDescr)"></xsl:param>
<xsl:param name="ProductFroogleDescription" select="aspdnsf:GetMLValue(ProductFroogleDescription)"></xsl:param>
<xsl:param name="VariantFroogleDescription" select="aspdnsf:GetMLValue(VariantFroogleDescription)"></xsl:param>
<xsl:param name="ItemImage" select="aspdnsf:ProductImageUrl(productid, ImageFileNameOverride, SKU, 'medium', 1)"></xsl:param>
<xsl:param name="ManufacturerPartNumber" select="aspdnsf:GetMLValue(ManufacturerPartNumber)"></xsl:param>
<xsl:param name="StoreURL" select="/root/StoreSite/Store/ProductionURI"></xsl:param>
<item>
<title>
<xsl:value-of select="$ProductName" />
</title>
<link>
<xsl:value-of select="$StoreURL" />
<xsl:value-of select="aspdnsf:ProductLink(productid, sename, 0, '')" />
</link>
<description>
<xsl:choose>
<xsl:when test="$VariantFroogleDescription!=''">
<xsl:value-of select="$VariantFroogleDescription" />
</xsl:when>
<xsl:when test="$ProductFroogleDescription!=''">
<xsl:value-of select="$ProductFroogleDescription" />
</xsl:when>
<xsl:when test="$VariantDescr!=''">
<xsl:value-of select="$VariantDescr" />
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$ProductDescr" />
</xsl:otherwise>
</xsl:choose>
</description>
<g:image_link>
<xsl:if test="not(contains($ItemImage, 'nopicture'))">
<xsl:value-of select="$ItemImage" />
</xsl:if>
</g:image_link>
<g:price>
<xsl:choose>
<xsl:when test="number(saleprice)=0">
<xsl:value-of select="format-number(price, '###0.00')" />
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="format-number(saleprice, '###0.00')" />
</xsl:otherwise>
</xsl:choose>
</g:price>
<g:mpn>
<xsl:value-of select="$ManufacturerPartNumber" />
</g:mpn>
<g:condition>
<xsl:choose>
<xsl:when test="number(Condition)=0">
New
</xsl:when>
<xsl:when test="number(Condition)=1">
Used
</xsl:when>
<xsl:otherwise>
Refurbished
</xsl:otherwise>
</xsl:choose>
</g:condition>
<g:shipping_weight>
<xsl:value-of select="Weight" />
</g:shipping_weight>
</item>
</xsl:template>
</xsl:stylesheet>
</PackageTransform>
</package>
In this case this is really small modification to the xmlpackage. It comes down to adding the weight field to the sql statement and then outputting the newly added weight field in xslt.