Chosen material turned out to be wrong. These gears got out of tolerances just laying on a shelf. Seems to absorb humidity and increased its size by about 1%. Not too much, but enogh to have two issues:
1. Loose fit on the shaft.
2. Tight fit in gears coupling.
So, I'm selling them cheaper than their production cost just to not dispose them. May be someone will be able to fit them well - depends on tolerances and wear of microscope gears.