RE: Stock Fin For Carve 145
OK, sounds like you are pretty seriously underpowered much of the time.
Good 7.5 and 5.5- 6.0 free ride or free race sails would probably help your progress alot. Don't need any cams (but a cam or 2 is OK, but try to buy either something new or designed within the last 5 years (if you buy them used).
6.5 - 7.5 m2 is an OK gap. The gap needs to get smaller as the sail size decreases.
What wind speed do you sail in most often?
A modern 7.5 m2 rig should be good for a guy your size from 10 knots to the 15-16 knot range if correctly tuned
Your 6.5 Pilot should work in the 14-20 knot range and the 5.0 older Tush in the 20 + knots range.
Hope this helps,