From the inside is easier, I like to find some Laminex or similar material with shiny surface to attach to the outside of the hull
so it acts like a mould. I usually use polyester on the inside and make it as thick as the hull. Then the oustide I glass with a layer of 450gm double bias in epoxy
. Using polyester on the inside means you can use flo coat to paint
the inside of the hull. It also lets you use chop strand and some heavy woven rovings. You should be able to get the repair flush with the hull so you can not even see it was there.
Its a bit hard to describe but I mould the laminex over the hole, then from the inside glue another peice of laminex the exact size of the hole onto the mould. That way when you remove the mould you have a 2mm indentation. So then you grind the exterior hull 100mm around the the hole to match the indentation and cover with one layer of epoxy/fiberglass and peel ply. Then it is basically a bit of epoxy filler and a quick sand.