Hey there, I currently use a D4 to trigger the practise kit I've converted into an electronic kit. To start with I tried using the original heads/foam that came with the kit but after much experimentation I found that the best way is the use mesh heads with off-centred triggers. Just mount the piezo like this camera film canister cut down to size > foam insert for canister (make sure it's out the top of the canister) > piezo > a closed cell foam to touch the head itself (something like a Nerf dart) et voila! You can get everything on the cheap from birmingham drum centre, I think around 80 for the kit, 15 for a set of plastic cymbals to trigger and 5 each for the mesh heads! hope that helps you! p.s. any more info head to electronicdrums.com or the Yahoo DIY E-drum group (sorry don't have the address)