Hi Mick!
Welcome to the Forum; nice to have you aboard!
Here is Rohloff's official statement on chains...
All 1/2" x 3/32" eight and nine speed chains are suitable for use with the Rohloff SPEEDHUB 500/14 although we recommend the eight speed version due to its slightly thicker link plates. All 1/2" x 1/8" bicycle chains are also compatible with the Rohloff SPEEDHUB 500/14 sprockets. These thicker chains however are by no means stronger and not recommended for use with the Rohloff SPEEDHUB 500/14. In addition to this, they are not designed for the high mileages achieved with a SPEEDHUB and thus are subject to faster wear. These 1/2" x 1/8" chains are also unfortunately too wide to pass through the Rohloff chain tensioner.
...from:
http://www.rohloff.de/en/service/faq/faq_detail/archive/2005/11/july/article/Bike_Components_which_are_recommended/index.htmlWithout grabbing my calipers, I
think a 10-sp chain would be too narrow to run optimally on the Rohloff
cog, even though many single-speed
chainrings are listed as being compatible with 10-sp chains. Not saying it can't be done, but I have my doubts. If you don't get a definitive answer, I'll be happy to measure my Rohloff's cog thickness and check it against inner chain dimensions.
I can understand your desire to use up old stock, but I also have some concerns the 10-sp chain's thinner plates and roller would result in accelerated wear of the entire drivetrain compared to the 8- and 9-speed chains Rohloff recommend above.
Hope this helps.
Best,
Dan.