Gap in the forms shouldn't be so wide that the hose is allowed to fully expand. The rounder the hose gets, the more it will transfer the roundness to the belly of the limb...even through pressure strips.
Yes Bue, the hose I sell is the same size as the hose they sell only I offer mine as a double jacketed for extra durability.
I also understand the need in being frugal. I tried very hard to come up with a cheaper avenue when I first started. I figured out that by the time I made something work, I spend countless hours chasing parts and then assembling them only to save a couple dollars or even spend more.
Thanks ,bigjim