Would have been a good idea to check a couple of things before tearing it down, but it's not to late to soft-install the existing bb and torque on the driveside crankarm to check for chainring clearance (you need 2+mm here) and chainline (carefully sighting along the sides of the clean chainrings to ascertain good centering with the freewheel's width).

Then measure the existing spindle's symmetry to be sure, and lastly order the needed bb spindle length bottom bracket.

I almost always shorten the driveside chainline dimension, to allow full-range usage of the rear cogs when in the big chainring.
For numerous reasons, I never use the small chainring with the smallest couple of cogs, so I have a slight bias for shorter spindles.
As well, the less expensive bikes from the old days always had way, way-overlengthed spindles to mitigate consequences (chanring rubbing, etc) of riding with both stem shifters left full-forward.