I bought a used '91 trek 7k with Deore DX, the last year they used ball, cup&race bottom bracket. The chainrings need replacement, and the BB has some decent play in it (enough to make the chain rub the front derailleur on the left foot stroke). I cleaned and repacked it (temporarily reused the caged bearings), but couldn't tighten it enough to get rid of the loose play in the axle. Is that something which might be overcome using 10 or 11 loose ball bearings, intstead of the 9 caged ball bearings? There is some pitting on the axle races, but not too bad, and the cups are smooth.

I suspect that the axle is worn out, in which case I'd probably replace with a catridge, when I replace the crankset. BB shell is 68mm; the crank axle measures 133mm end-to-end. Crank appears to protrude 4 mm farther on the chainring side. This seems to match a discussion from rec.bicycle.tech
Help: Replace 68,133 botom Bracket - Google Groups

I'm guessing I could get a 68x130 Shimano tapered-square, which would be put the chainrings 5mm inboard. I could use a triple crank with the inner chainring removed to gain-back about 4mm. I'd prefer Octalink, but don't see many long options. Does "120mm" mean the same chainpath whether you'r eusing tapered-square vs Octalink?