Hey Diastro......with mine, there's a ever so slight vibration but once the shaft reaches higher rpm it disappears.....one sure fire way to test the shaft for bends is to completely remove it from the heli and roll it on a smooth surface and get down to eye level with it....can't go wrong that way.

As for the lower blade starting first, same with mine but it's jus for a millisecond or two before the upper and i have my pots tweaked perfectly.