Anybody have any ideas for a do-it-yourself solution to the hook on the back of my 1989 formula 242 hull?

if you have a straight edge, inline sander and know how to gelcoat, dig in and don't go to far.

On my last boat I used 2"X2" angled aluminum about 4 foot long. If you use a shorter piece you may not get the bottom as level as you want. You may also put more low spots in. Take your time and keep checking with a straight edge.

That hook was built in by formula, They may have do away with it in the early 90`s.