Very strange, as I've said earlier, a lot of 16mm scale locos are gauge adjustable for 32 and 45, usually by moving the wheels, so they must be compatible.I go back to my scratchbuilt 2-6-2 (piccies are on my other computer I'm afraid) but it runs on Slater's 44m diameter drivers made for the 16mm : 1ft GRS kit of the Lynton & Barnstaple loco. I haven't measured the tread width, but I expect it to be about 4.5mm.
When I first built it, I had an LGB R3 turnout on the layout, an Aristo #6 and a USAT #6 and it ran through them all without difficulty.
I currently have Aristo 10 ft and #6 and a USAT #6 turnout plus an LGB diamond, and the loco runs fine.
I'll do a bit of measuring in the morning. The wheelbase is longish, so the middle drivers have had the flanges turned down in a lathe (someone did it for me) so they are blind.
There shouldn't be a problem - there are plenty of people in the UK running wheels to 16mm Association standards on LGB and similar trackwork.
As an aside, the back-to-back for 32 mm track is 28 mm - so add 2 x 4.50 mm = 37 mm - only 5 mm wider than the gauge, but for both 32mm and 45mm gauges, the Association standards are for 1.5 mm thick flanges