A link to the original thread for the Dual Zone Drop in Pan Conversion: http://www.vdrums.com/forum/showthread.php?t=56650
And just so we have this in a good place.... The attached image is the...Correct Wiring Diagram for Splitting the Aux. input of the TD-12/20.
The splitter for those who won't or can't build their own:
Update: Trigger Foam for DIY: Page 3435: 3/8" thickness Is:86375K143 1/2": 86375K144 http://www.mcmaster.com/
For making just a few cones .... just buying the 1/2" sheet will be ample to make more than needed. 3 layers makes it 1 1/2" high. For DIY projects that height would be fine ...... That is a little taller than a Roland cone. 2 layers of 1/2" and one layer of 3/8" is a height match for Roland cones.