Originally Posted by
Revracer
I will keep a close eye on that as I am no lightweight at 195lbs on a good day and packing a rear rack for commutes. If this truly fails in that area, I will explore either a custom freewheel (hoping with modern tooth profiles) or will just relent and go freehub since this is a rider that needs to be reliable, but vintage appeal with the other appointments.
One measure to reduce risk is to have your frame cold-set to the new dimension (130 old) and the dropouts aligned to be parallel at the new width. It's not a lot of difference, but it will eliminate one source of bending stress on your extra-long rear axle.
If you can build a wheel with a cassette hub, that will be better, but the frame and dropouts should still be cold-set for good alignment and to minimize stress on the hub.