torque convertor

My impression is Lenny thinks the work involved is too close money wise to a new one - you "might as well" replace it if you're spending 1/2 or more to fix it. Hughes doesn't care they just want your money.
Personally I use intended use for the first driver of stall speed. They are always below the peak torque because these are street cars, then race cars. IMO, the convertor is probably not the best tool to tune with, unless everything else has been done already. If you can get it to work optimally, the convertor may change a little anyway (it will feel the load more).
I'd probably give the welded tooth a try. Teeth get worn from the process of meshing when it first engages, not usually from the torque of spinning. So something there will help that meshing process.