From trying a few simple things in the summer the folks at
- Easy Composites
were very helpful, videos on their site too (they have a specific learning page).
Manor wood is great with good principles, but these are big projects!
Main learning points for me was mixing ratios - weight was easier than volume
Taping the piece with the correct tape did make life easier, in terms of leaks and releasing after setting
Temperature in the room you are pooring even small quantities, if the tin says 60 degrees as a minimum (this includes the night time temps), then that's the minimum, it made the difference between a 3 weeks and 2 days to go off.
For just trying stuff I wasn't going down the rabbit hole of vacumn chambers, but a heat gun (I already had but is cheap to buy) helped hugely combined with tapping the work piece
Pouring is the first half, cutting back and polishing is definatly the other half
I wanted to fill a large knot (50mm depth and diameter) with brass powder epoxy mix, using powder and super glue to fill the little imperfections around the knot (shallow sections lifted out with sanding) then coming back fine sand paper.
Cheap polishing drill attachment provided a good final finish
Hope that helps