After some research, I used a mix of 2 bags of http://www.aquabuys.com/miva/merchant.mvc?Screen=PROD&Product_Code=crs_aragamax_30&Category_Code=l7&Product_Count=5">Aragamax</a> mixed with a bag of [IMG]http://www.aquabuys.com/miva/merchant.mvc?Screen=PROD&Product_Code=crs_sand_seafloor_40lb&Category_Code=l7&Product_Count=6">Carib Sea Floor</a>. If you need more, keep adding Aragamax.
As for depth, 3" is just barely starting to scrape into deep sand bed territory. I'd suggest either going 4" or keeping it to 1" or less (i.e. just aesthetic).
The variation in coarseness makes for a better sand bed. Avoid [IMG]http://www.aquabuys.com/miva/merchant.mvc?Screen=PROD&Product_Code=crs_live_oolite_20lb&Category_Code=l7&Product_Count=0">sugar sand/oolite</a> in my opinion. It does look cool and takes less to make a deep sand bed, but I don't think it's as good an environment for organisms and it will clump more.