Just had a 23 Seacraft soda blasted to remove bottom paint. Paid $600. Had to fill and sand some but not too bad. We were going to Alwgrip the whole boat anyway. Just have to make sure the person operating the soda blaster knows what he is doing. There is a new system out. Farrow System. I read some and even talked to the guys. Sounds like it would be easier on the fiberglass. Main operation is in SC. Check them out.
http://www.abrasivecleaning.com/