Not that I know of. I would just always use 4% by volume. I think that comes out to a quart of toluene for every 5 gallons of mixed, finished fuel. It doesn't screw the specific gravity up much. If you're running 10%, 50% 70%, whatever, a quart will do the job.
If you're running nitro on the "AFR" method (75% or less and somewhere in the 2-3:1 AFR range), injected or supercharged - then just run a quart per jug.
If you're running the "Volume" method (less than 1:1 AFR) supercharged, then a quart will work great.
If you're running the "Volume" method injected, I wouldn't run any toluene. If you do, be ready to scale it back if you start putting out/dropping cylinders. At 10 GPM of 98% into a 392" motor, I started putting out a couple of cylinders occasionally. I stopped using toluene and not only did that stop, but I upped it to 11 GPM and it's still going strong.
So, toluene has it's place to help desensitize the fuel to pressure and it makes a big diff in keeping detonation at bay and the head gaskets in it. However, in some situations (high volume), it appears you need the stuff to be fairly sensitive so it'll go off for you!
