So, in feeling around the part, I’ve found a few small undercuts where I’d repaired the gel-coat with more gel-coat. I went around it with my fingers to look for issues, and found a few where the repair I’d done accidentally still went in a little, like a dimple. I’ve started using Dolphin Glaze as filler – it’s really thin and spreads well. It also comes in a squeezy tube so application is easy. I also bought a pack of onion paper for mixing on – wish I’d done it much sooner.
It’s styrene based though, but because I’m spraying in a barrier gel-coat first, I’m not concerned.
So, next is to make a 2×2 frame and apply plastic sheet to keep the dust down, and then I’m making cloth templates.