Interesting test to determine the precision of the bolt circle diameter. I have not paid that much attention to the condition of my crank and chainring combos, but I can say that if my chain was just right in the loosest spot, that rotating the crank would find a too tight spot. My highest quality crank/ring is my All-City 612 and it's also the most precise. I would expect the C-Record Pista to have pretty tight tolerances.

but based on the ~.5mm estimate I think that your "too tight" is not actually too tight and that you can just back off the tension a bit. Make it just right at the tightest spot and as long as the chain does not fall off in the loosest spot you'll be good.

You can also loosen the chainring bolts and tighten them as you turn the crank. Take a look at Sheldon's article. Scroll down to section "Centering chainrings."

https://sheldonbrown.com/no-derailers.html