Torq2.1 baseline settings?

[Fastech]

Hi all,

Just installed the Torq2.1 on my '11 F350 tonite, and I'm looking for advice on a good starting point. I've got 3.55 gears and 325/60R20 Terra Grapplers (a bit over 35" tall). Reading over the supplied notes, looks like 3.55's call for position 1 on the dial with stock tires; trying to compensate for bigger rubber (with public school math skills lol), I've tried pos. 1, pos. 0, and pos. 9 so far. With the knob up to 100%, it falls on its face like you've cut the throttle when it hits 3rd (and sometimes starts shuddering as well, like the TC is confused). Dialed back to 75% produces the same results, while 50% seems to clear it up- but OF COURSE I wanna crank up more than 50%!!! Lol. It feels best on pos. 0 or 1, and the directions contradict themselves by later stating that normally you'd use pos. 0, 5, or 6 regardless of gear or tire size.

Can anyone give me any advice as to what settings to start with for the most power and mileage?

Thanks!