I held the piston in between my index finger and thumb... bored out the stock 1.7mm holes to 2.0mm with a regular drill, no fancy press. Scraped away shavings with a hobby knife, then used a sharpie to label 2.0 on each piston.

I've been meaning to try 2.1mm but had too many other setup changes to play with first. I kinda like using the same fluids front/rear with the 1.7/2.0 setup