Maybe at the end I will try International Perfection Plus, since it is two part and should be the hardest one.

Perfection also requires less build thickness (2 to 3 coats) instead of the 4+ for regular varnish and cures quicker (8 hours per coat versus overnight) so you can be on the water quicker. Less weight. Being harder it also polishes easier. I found it lasts longer to boot. It's two-pot but is easy to use. The fumes from the thinner can be pretty rough though. Good call overall.