Yeah, was thinking the paper could tear if not exactly the right thickness.
Decades ago, as a kid I read of double bench rest muzzle loaders, for match shooting, that used a conical type ball made in two parts. Front was hard lead to resist deformity when loaded, back was soft. I also believe the patches were a "X" shaped patch that exactly covered the majority of the projectile. It had no grease grooves, again, if I recall correctly.
Perhaps a similar strategy could work in inlines? Make an X shaped patch instead of plastic manufactured sabots?
Unfortunately, I can't recall the twist rate of those old bench rest match rifles.