"reduce the torque, inverse to pitch"
Suggest you do some research on this one. The fraction of torque actually translated into tension is quite small. By quite small I mean 10-15% The balance is under head and thread friction which is the same regardless of thread pitch.
So- 14 TPI versus 20 tpi only changes the 10-15% number, not the total torque so the difference in torque will only be 2-3% or so of the total.
This is why thread lubricants are so important, to control the thread and underhead friction which is 85-90% of the total.
If you really want to dial in the fastener tension you need to test or measure stretch.
