Ok, 5 to 8 inches - that's what I will work from then.

Probably easier to start at 8 and trim it back down but what concerns me is the volume of the canister may not be large enough to resonate at those lower rpm.

And by the way, full length pipes can be tuned as a means of control at control line stunt rpm so here is hoping that the MVVS folded pipe can be too!