I am not sure what leaded lights are but i was thinking of adding windows but with a ladder and outboard I think I will be struggling for space. You are dead on about the blister, I found a lot of water and a strong smell of the forrest after rain in it. I just kept digging back to good wood though.
I made a template to replace but as I often do made a mistake and cut the wood in the wrong direction. My old man is much better at that than me so he helped out for this bit.
I must have been having a bad day though, I mixed my epoxy and is good practise wetted out the surface with raw epoxy. the main reason from my research is that the thickened epoxy has less area to cling and is is possible dry wood can wick out some a dry out the joint. i then mixed up my peanut butter with filleting mix and microbubbles. I done my work then again as is good practise put the extra out in the open. After 5 minutes later chatting I noticed smoke coming from the tub. My scale took a wobbly and I think i added to much of the epoxy second part.
it has set solid but I have lost some strength for sure from the unreacted part of the mix.
my Failed attempt
old mans one