Personal preference is to get as much power as I can and when I go to a lower grip outdoor track play with throttle profile and/or current limit.
I find the throttle profile adjustment to be much more effective than expo on the tx.
Have actually been playing with no current limit, high timing and THP at 2 and like it. Smooth if you want it but grab a hand full and your off like a rocket.
No time limit of current. It's 100% if your throttle finger asks for it. Current limit limits you to the value you set it at for a few feet of the initial pull on throttle.