Basically I would like to know if there is any benefit to running in T/H with a higher tune?

Does the T/H mode help to prevent transmission slippage/limping if you are running a higher hp tune on a stock Allison?

I do realize that eventually I will need a tranny upgrade.

When in T/H mode the tranny drops line pressure which means that you will have less holding power. I am not sure how much it drops or if it drops enough to be the difference between you limping it or not. T/H mode is faster in the 1/4 mile. T/H mode keeps the tranny cooler when running hard. I would stay away from boosted launches and out of 5th gear under WOT. Downshifting from 5th to 4th under WOT does the most damage.

T/H drops Allison pressure from the standard 250 psi to about 150 psi. Yes we have a drop in holding power but we took a lot of the torque multiplication from the engine away because with the converter clutch applyed we are in direct drive. This does take a load of the clutches to a point.
mike

t/h increase's pressure,and locks the converter clutch in.I thought?