Going over the bars is part of the game. It sucks, but we all do it from time to time. You definitely need to learn to tuck and roll! LOL
Seriously though, your questions are all dependant on the individual.
I would suggest that you go and get yourself a proffessional fitting, that would eliminate a lot of trial and error of moving and changing equipment, and while it might cost a few bucks up front, it will save you in the long run.
Some of it though is riding technique, and learning to properly shift your weight and when to shift your weight.
Is this happening on downhills, like at Alafia, or does the happen at Flatwoods?
Yes you can have your fork too soft. What kind of fork do you have? Most have multiple adjustments that can allow you to have a plush ride, without bottoming out a lot.