DIY Bed Foam and Latex Mix

[drolph]

I'm thinking about "building" this mattress:

• 4" or 5" HD36-HQ Foam Base from FBM [FONT=Arial, Helvetica, sans-serif]-[/FONT] http://www.foambymail.com/HDHQ_2/hd36-hq-foam-mattress.html
• 3" or 4" 5lb FBM Foam middle - http://www.foambymail.com/V_5/5lb-memory-foam-topper.html
• 3" Talalay latex top (Soft: 22-24 ILD) from Mattress 247 on ebay - http://www.ebay.com/itm/3-100-Talal...71121907084?pt=Mattresses&hash=item3f201ffd8c
• Terrycloth Cover

Me and my fiance like a medium-soft mattress. We tried this overstock mattress at a friends house and liked it, but I though I could DIY something better.
I put latex on the top instead of foam, because I wanted the bed to not be too hot. Should the latex be in a seperate cover from the rest? The only latex we tried in person was the latex at Ikea, which was too firm for us.
Thans in adavance! -Danny