Tell you what...
Next time, or for anyone else building a PDR MK III, build your daggerboard box first. Or at least as soon as the sides are cut so that you can get the correct profile for the box.
This is the bit that is hidden inside one of the side air boxes that the daggerboard (not a centreboard, not a leaboard, must be a daggerboard aka, the 'keel') goes into. This is because it takes ages to make due to the surface finishing that happens inside the box before you do the preliminary assembly. Have to do all this painting first because you can't do it when the whole thing is stuck together; you can't reach the inside of the box.
First you epoxy it, then you undercoat, then you top coat a couple of times. Each time you have to wait between 12 - 24 hrs for epoxy/paint to dry. As this bit gets as wet as the external hull, you have to make sure you paint and seal it well. You don't want it leaking into the air box.
I'd also buy the gudgeons nice and early so the tillerbox and tiller can be put together completely. That is a fun job to do. I've really enjoyed making that part and it looks really nice. Lots of nice, clean, varnished wood. Looks very nautical.