One more thought
Two important points:
You have to prepare the surface appropriately.
Everything has to be structurally sound before you start the fairing.
I used to be too 'timid' when I started doing carbon repairs on thin hulls, always concerned about weight and not disturbing the elements that were still intact.
Now I am more generous, the surface has to be entirely cleared of paint etc., any exposed core material has to be dry, if you have thin core and an inner layer, consider to remove the core and start building up against that inner layer.
Strength as needed is the most important aspect of your repair and of course it should not leak.