I run the OS#3 with 30% trinity platinum fuel, I have also run the OS#8 with this fuel,both work well for me!The #3 are cheaper and very versatile plugs.
With 20% fuel I've always used OS#8. They have worked very good for all my cars and trucks. They are pretty much all I use. There are less exspensive plugs but I stick with what works for me.
In case you do not know. Each plug manufacture and number are a different heat range. It can get complcated and there are web sites out there with explainations on how to read what te plug is telling you after it is run in a specific engine.