I'm trying a mix of one gallon of toluene to a full tank of 93 octane pump fuel, to see if there is any appreciable performance difference. Without a logger, this is all going to be "seat of the pants" testing, but we'll see how it goes. Realistically, this is more a test to prove to myself that it's a non-harmful mixture than anything else. There's more information available from the folks at gnttype.org, if you're interested in this kind of thing.