I have an 89' F150 std. cab, short bed, M5OD-R2, and I have 6" and 35's.
4" of lift they recommend 33's. Its a pretty nice look. For 6" of lift they recommend 35's. Bot have the same gap. Its all on personal prefrence on how much gap you want between tires and fender wells.
Next, 3.83's isn't quite enough for 35's. If you have a M5OD-R2, your clutch will slip, like mine does. I have 3.55's. But for 33's it should be fine. But I believe they recommend 4.10's. For 35's, it calculates out to 4.30's, but w/ 4wd, you can't get 4.30's for the front D44, so next best is 4.56's If you a 2wd, I would go for the 4.30's personally if you go the 35" route.