My current idea is to get an ABUS 10KS sleeved chain, and the armored lock that goes with it 92W/65.

What length would you recommend for the chain, for use in a variety of circumstances?

I am estimating that a 5' chain would allow me to loop through both of the wheels and the frame, but it might be a bit heavier than I want to lug around. I think a 3' or 3.5' chain would get me one wheel and the frame.

What would you recommend?

PS, my commuter bikes are an older Fisher hybrid and a Volagi Viaje if that makes any difference.

If weight is an issue, go for enough to secure the frame and one wheel. Then pop off the front and put it with the back with the chain through both.

I own a Chain and Lock combined Abus . straight from catch to pin it's 1.1M.

with a hex ended Skewer, where I live , wheels have not been attempted to be removed.

My R'off Trekking bike has a ringlock & Plug in security chain that is 1.4M long on the end of the chain, a bigger loop
lets the pin end pass through..

Defender*-*axa-stenman .. https://www.axa-stenman.com/en/bicycl...hains/rlc-140/

then I secure the front wheel to the frame, and the chain passes around the rack, or steel signpost..

Skip the chain. Use a u lock. Hobble the bike. Take off the front wheel and place it next to the rear wheel. Put the u lock through both wheels, the frame and a secure pole/rack/pipe.

these are easier to carry than U Locks .. ABUS folding locks - Locks / Bike safety and security

this is their most secure .. ABUS Folding Lock 6500/85 black (55160)

I would advise against going for both wheels with your main chain for security reasons.
For me, an ideal length is 1.2m. It allows to attach 1 wheel + frame to most posts without having too much loose.