In my case i did also source an original NOS UG 6 speed chain as i thought i had to use UG chain with UG cassette, but i have no objection to using a narrower HG chain if it might work better with the thinner 10/11 speed Sugino chainrings. I may go with LGF's suggestion of 8/9 speed chain and have some chainring spacers on standby to fix/reduce chainring rub. Thanks all for your advice.
