Dar, while I commend you for trying to get this running in process sorted out I think you've made an assumption as to why Jett recommends the initial very rich run (yes, about 1 minute) to bolster your case. In fact he doesn't give any indication on his site as to why he recommends it. It could just as well be to ensure the rod ends are thoroughly lubricated before leaning out to high speed.

I think it's safe to assume that if OS or other lesser engines can hold tolerances to the point that those engines have similar pinch when new then Jett's don't need to rely on a "bad" rich initial run to hammer the piston down to an acceptable fit.