I use a cheap Home Depot carpet, that the velcro (on the bottom of my pedal) grabs. Almost have to tear the pedal off the carpet. I think it's mostly a carpet issue. Too thick (being 3 ply) and too slick. I currently have two 26x14's (Ludwig and Gretsch) and have had two others before ( 26x14 and 26x16 Ludwigs). And I always run 'em without mounted toms, virgin or not. Never had any hop. I think it's a carpet issue.
I would tend to think this the major contributing factor. I will also take a close look at the height if the front of the bass and bass pedal spurs. I am in a little bit if a learning curve with my new kit. First time with curved spurs, virgin bass drums, and large 26" bass drums. I will get it sorted.