For starters just play with the forestay. Get a base setting for about 10-12 kts and go 5 turns on for big breeze and 5 turns of for very light, and adjust as nessisary for the in between breeze.
You cant adjust while racing but do it between races. Allways know where you are with it, normally you just talk about it as '+1' as one turn on and so on and keep talking about it and where you are at all day. You need to go back to base at the end of the day. Have a small bit of batten with marks on it to line up if you loose where you are.
This will make a massive difference to your pointing an