Advice I have heard in the past is to sand the trailing edge with a block so there is a small square edge. This was even for slalom fins.
The other strategy is to wear protective booties. That's my way.
And before people jump in with the "can't get the same feel of the board" thing, I can say it makes no difference after a short time to get used to it. I am a keen surfer and wear booties all the time and if it was going to make a difference, it would be more noticeable there and I dont think it makes any difference at all
. Booties and 'feeling' is all in your head.
YMMV.
