I wouldn't worry about the angle of your tail on the runway. But the angle of you wing matters a lot. I set my nose gear planes up as close as I can to 1/2 degree of negative incidence on the runway. And I set the main gear so that the nose wheel has very little weight on it, just enough to not worry about it tipping back. In fact, the best landing plane I ever had was my Intruder pattern plane, which would rock back on the tail when there was no fuel in the tank.