don't take me wrong it is great that you are pretty keen, and I understand that you want to maximize your time on the water..
but sails with cams is from my point of view particularly slalom/race oriented.
You 've mentioned the problem with waterstarting and I could bet the next thing will be that handling the sail in the gybe is difficult..etc.
I am sure you could get a 6.4 freeride style sails without cam.
If your interest is just to go fast and race your mates then ignore my comments.
If you want to go soon into little wave/chops then a freeride/freestyle board and big freeride sail will definitely help you to learn quicker lots of new moves and to be generally looser when you ride.
I've just seen lots of guy getting stuck into the slalom bit just when they were in the full progressing phase..and the cams sail was usually the start of the end

Anyway, I've read that you are doing pretty good progress, this is cool.
Keep goin and good luck !!