You didn't specify what year mainshaft/trans you want to use. I stuffed an EL knuck motor into a VL and had to use a 65 - 69 mainshaft to line it up. I started with a year 1974 trans and changed the mainshaft. I don't know if the VL sprocket shaft sticks out the same dimension as an EL knuck, so my method might be only half of your equation. The idea of two clutch fibers in the hub doesn't sound like a good idea. Hanging the clutch drum that much further out will increase the leverage on the mainshaft at the least and the bearing surfaces vis-a-vis the hub and drum mating one to the other might present another problem.
If I were you I would try this: install the engine with the motor sprocket;
install the trans with the clutch hub, pack, and drum;
take a straight edge and check the alignment on both sprockets.
In my experience, off a little bit hurts nothing. Off a lot, and right this minute I can't remember in which direction, will mean your clutch is always engaged no matter what you do. I started with a 1974 (long) mainshaft and had to go shorter. I did not try a 64 and earlier shaft because the 65 - 69 appeared to line up, which it did, and everything worked fine. You will have to use a 65 and later trans case for the bearing support if you any 65 and later mainshaft. Do not cut the aluminum primary support ears off of the case. Just remove the 4 studs. The 65 and up cases are stronger in the main drive gear area because of those ears and the extra metal.
At one point I even considered moving the engine over but the more I thought about it I realized that was an exceptionally stupid idea. Matching up the mainshaft as I indicated above and using a Superglide clutch arm /eliminator style gave me a flawless clutch.
New Knuckleheads? Thank, you, Jesus!!