Trajectory ~I am not sure we are all talking the same thing.
Assumtion, front toss is about 15' from batter.
I am not going to say this right but a riseball does not rise. All balls are coming down a little bit.
So if you sit and throw over hand it seems fine to me, close to line players will see in game. If you sit and throw underhanded seems bad. Play slow pitch.
Standing From 15' I would throw underhand.
Again not sure which one is better then the other.
Well, I don't think that standing underhand toss from 15-18ft equates to a pitch from 35ft trajectory wise, although velocity is also a factor. But I suppose I should take some video and take a look at this. Plus 10 pitches to 12 players is a 120 throws. But in the end it comes down to accuracy, I can dart throw the ball to spots better than I can when I underhand it. Ball spin is not a factor.