Sweet frameset! The world is certainly your oyster with regard to component and groupset compatibility. Others have already said plenty. As for square taper bottom bracket spindle lengths, you may have to do some research, though by the late '80s Shimano (at least) had streamlined their BB spindle lengths. If talking about Dura-Ace around that time--previous cranksets would employ 109-111mm or so BB spindles. When Shimano went to 8-speed, they redesigned the crankset ("7410" is stamped on the back of the arms), making it more curved and also accepting of a much narrower ~102mm BB spindle. Hollowtech (aka Octalink) for road ("V1" designation, almost exclusively) went to two lengths as T-Mar said, depending on double/triple. Hollowtech II (external bearing cups) BBs for road (at least, all I know) were only one type. A double crankset had a standard spindle length, and a triple would come with 2mm or 3mm spacer(s) for the longer spindles. The spindles on Hollowtech II cranksets were attached to the drive side crank arm/spider.