Omni is hard to beat for the hobbyist and even the professional shop that needs a value line product. It's a nice affordable system from undercoats, single stage, base/clear etc. Omni plus basecoat is great. They have a few different options for clear from production to overall/complete clears. MC161 is my favorite omni clear 2:1 ratio. Limco(basf) 4100 or 4200 are also great value line clears.
However I have used a lot of finish one products or Sherwin Williams, but not clear yet. Just primer surfacers and sealers, and honestly have never been disappointed. Next project I'm tempted to try this. My local NAPA carries it. Don't overthink mix ratios. Just mix per p sheet and slower is always better than faster if you question temp range.

https://www.amazon.com/Ultimate-Overall-Clearcoat-Hardener-HARDENER/dp/B01MR96I32?th=1