an icon subforum would be a waste.. you can just as easily get all the answers you need in here right now so it would be of no benefit.. stacked tube blowbacks are just that.. and there's very little if any difference between the moving parts in them... i could see if it operated differently or whatnot but they dont, so just keep posting in here
and about an owners group.. i dont think it'd get too much traffic, but if you wanna make a anner and group go right ahead and see how it goes! maybe we're mistaken and it'll work but i wouldnt get hopes up.