The back side just looks like a regular pedal v1 clutch, everything the same except that extra plate with the teeth is riveted onto the side on top of the starter face using the same rivets that go through the clutch. If you look at Todd's pics, that's exactly what he did, took the machined hub out and welded it in, not a bad idea.
I gotta use the taper crank because I need a needle bearing con rod, I've already got the new crank, it's really very simple to just machine a bushing with the taper on both sides, cut a pocket into the front and either tack or maybe drill and tap the 4 holes where it's riveted now.
I'm gonna do a full rebuild anyhow since I gotta swap cranks so I'll update next week after I get back from vacation.