Re scanning film and resolution. I have no dog in this fight, but back in the day I used an Imacon LF scanner. No, the Imacon was not an Aztek drum scanner, but it was pretty darn good. Anyway, I (and others who shot a lot of LF film) found that in most cases, 1800 DPI was around the maximum point you could extract detail off film -- the best low ISO slide films, neg films went a little higher -- anything higher usually just enlarged grain and gave no real additional usable image detail. And I would probably not argue with somebody claiming they see a wee bit more at 2400, but beyond that, you're chasing windmills.
Point 2: Regardless, 745 is not everything a perfect 8x10 has to offer. However, let's keep in mind that if it already looks soft at 745, it 'aint going to be any better at 8000...
Point 3: Lens resolution really depends on how you test. *SOME* LF lenses with 300mm or larger IC's are capable of making 60 line pairs, most are not -- I know this, because I tested a bunch back in the day. (The 150 APO Sironar S will NOT cover 8x10 -- the uber rare 150 APO Sironar W fall just shy of covering fully, but it was close enough and is a cult status optic -- and note it's a BEAST by comparison to the 150S, like 4 times as big.) Seriously, 30 to 40 line pairs was really good for an 8x10 lens. Note however we're not talking center-field here, we looked at 1/3 out from center to have a usable average number. So yes, if you are only talking center field, 60 is probably doable with a few of the best.
Cheers,