Since you're already using the Amsoil, go with GeeBeeJims method with all of them at 80-1. There shouldn't be any problems at all. I already do the same, but instead of Amsoil I use Motul 800 and Redline. The biggest difference is in the brand name only. At work we use only off the shelf WalMart 2 stroke oils mixed at 50-1 for all our engines and the 50-1 mix just makes a mess with a shorter plug life. We DO run at higher engine loads and aircraft weights, tho