I decided to cut my keel high density pieces right away, so I could get started on sealing them. I'm using good quality stuff - Okoume BS1088 marine plywood. Here's the trial fit:
Most of the keel section is (fortunately) perfectly flat, but up by the bow there is a bit of a curve that I know I'd never get the plywood to conform to. So I took the liberty of tapering the fwd 8-9" or so, as you can see above. After trial fitting the keel pieces (two of them per hull half, total of four pieces) above, I layed them out on saw horses and applied three generous coats of epoxy to seal them up. Tomorrow I'll sand them briefly before I mount them in the mold, since you always get some epoxy goobers hanging off no matter how careful you try to apply the stuff.
Here's the cut-out for the the keel strips:
Just a few more inches of gunwale left to plank, and then I'll be ready to start bogging between the planks!
I am very pleased with how the lower hull half is hugging the forms - the lines look very nice to me. I am not so pleased with the job I did on the gunwale strips and how they join the lower hull -- turned out a bit sloppy. But I don't feel bad enough about it to redo any of the work, having plenty of faith in the power of bog to fix most if not all mistakes.
On bigger boats, builders will often run electrical wire or conduit inside the foam at this stage (pre-lamination), so that the wiring is hidden from view. I've decided to not do this, mainly because I don't want to complicate the building procedures too much.