Hi!
I mix my own fuel since I started flying R/C och CL 36 years ago. I use 15% all synthetic oil (Aerosynth 2 , Aerosave and Motul "Micro") and 5% nitro for all my engines, both two and four-strokes, except for my small COX engines that run best with some Castor oil and 25-30% nitro.
But as you live in the US and perhaps have no retailer that sell those modern synthetic oils its best for you to buy ready mixed fuel. There are several manufacturers: Powermaster, SIG, Morgan for just naming a few.

16%-20% oil, either Castor or synthetic or a blend is what is mostly sold in the US. 15% nitro is the norm at your place, but 5% nitro is all it takes to have all (except perhaps Y&S four-strokes) engines to run just fine.

Remember ! There is no special fuel for either two or four strokes! These engiens can be run on the same fuel as long as the oil content is around 15%-20%.
Two and four stroke oil/fuel is something that was "invented" by some fuel manufacturers decades ago and mean nothing today and meant nothing then!