Dameetz,
I have done many races with one set of outdrives. The 42mm is really too short, I use 44mm or even 46mm sometimes. I use only the blue alu shafts. I think it's not a problem with running full lock. For longer runs it's better to use steel.
Overgear,
I sand both sides of the diff plate with aprox. 800-1000 sandpaper.
Adam,
Most of the time I just run it in in the car, half power and hold one wheel, then the other wheel. Then tight the diff little more and do the same till it's tight enough. Aprox. 30 sec in total.
Jilles