I've used the 70% rule as previously mentioned.  I have used TB in 13 different cartridges and honestly have not found it to be "gawd's" gift to the reloader.  Accuracy for all was only so-so, but I think it works better in straight-walled cases.  Mostly handguns...

I have used 9.0 and 11.0 grains of TB with the NOE 311-202-RN (210+ grains) for velocities of 1003 fps and 1107 fps respectively...

Accuracy was not great at all.  I think the velocity was a tad too slow for the 210 grainer...

Good-luck...BCB