I tried few diff heads on the 12" pads, they all fit perfect including the stock Mylar... The prob is with the billy blast head rims, they are too thin, I went as far as putting the diff heads together & that was my findings.
The foam I posted above & Remo single ply heads are much softer & minimal bounce... Nothing like hitting bricks! It was/is a huge improvement over the stock configuration.
Again I'm speaking from personal experience from my brand new DM10X kit.
Now if I had the "studio" kit, I would've taken a diff approach.. Hellfire method w/ BBII heads are a perfect combo for those kits!
I was going for an even feel between the 12" shallow pads & the 10" toms that make up the "X" kit. Having 2 diff type of pads on the X kit (shallow & non-shallow), the method/head combo I went with worked flawless for the 'even feel' I wanted