Buy a set. There will be other things that you want to torque. I probably have lots of extras but not sure I could put together a set for all bike related sizes.
In the first years of CAAD4, odd numbered sizes were available to be ordered as framesets. Perhaps that continued to be an option in later years but wasn't promoted in the catalogs.
I was working on a Chinese chain saw yesterday. Couldn't believe how tight a 3 mm screw that doesn't even need to be there was tightened. It just keeps a little plate from falling off when the bar is removed. When the bar is on it can't go anywhere. I had to go get a longer wrench.
Not a very good photo but it's my 1998 R4000 stamped 60 at bottom right as you read the numbers. I'v got a bunch of late 90s bikes and I believe they all have the size in this spot.
I once took a fresh build up to WI to ride with a friend. I'd left the stem slightly loose intending to do that but forgot about it. We were ten miles from his house when the stem came loose and of course I didn't have the tool to tighten it. Got a nice walk out of the deal until we found a...