Torque Converter question

Trying not to flog a dead horse, but I assume you have synced up the Transfer slots so you can idle it down some...
If the stiffening up is your only complaint than idle-speed might be an easy solution.
If banging into gear is a complaint, that can be changed too.
What can't be changed without a higher stall is a slow as molasses take-off with no tirespin.