extra strength required here^^^^
aside from hitting the odd sandbar or sinking the board when turning, i have heard my fins 'cracking' in their base when turning hard on a wave.
go for glassed in fins: fin boxes are actually weaker imo as they are designed to pop out of their base. old FCS fins broke (too) easily saving the base. newer fins have stronger bases so the fin box will come out before the fin breaks. replacing a fin box is probably easier to do yourself though.
also agree with bjw don't worry too much about deck depressions you will probably go get another board after a while anyway. if it is too heavily glassed will lose its lightness and flex.