You can do as you suggest and drill new holes, but filling in the old holes and dressing the edges of the
new holes is not really necessary.
My suggestion to elongate the existing holes forward has worked quite well on many boards with this problem
in the past.
Since the holes are slightly larger in diameter than the 6 mm fin screws, if you use a rat tail file that's approxx.
6mm an make aa nice elongated 6 mm slot it looks quite good and works really well.
What weed fins are you planning to use on the F-158?
If you can get one, the Lessacher Formula Duo works really well on boards this wide and the tip is only 40 cm