The 2 speed is dead easy to set up, just like the savage turn in the screw for later shifts out for earlier. You have to take the gears off the layshaft to access the screw though which takes a couple of minutes each time.
One thing I fould was the little steel pin in the carrier that catches the shift dog is way too wimpy, i've snapped a couple and pulled one out of the carrier destroying it. I now drill out the carrier boss, cut off an M5 shock screw FG part 6096, I cut the smooth shaft part down to size and hammer it in, haven't broke it since