Thanks again to Starchy for his help. The handrails were hot work in the sun, but they went on real easy. The hard part was making all the backing plates and fastening them on the inside first, which I had done over the course of the previous two days. Backing plates are 5" circles of ⅜" ply, needed because the cabin roof is only ⅛" ply.
As Starchy said, the handrails provide more strength to the cabin top. I like to think of them as an exoskeleton.
Once the rub rails were on, with the chain plates embedded, then I could finally raise the mast.
It was a little scarey because the ground is not level and the mast wanted to go sideways. The 5:1 purchase block & tackle worked a treat, though.
I noticed that some of the joints in the tabernacle had opened up a little from the stress of the mast wanting to go sideways—what fresh paint tells you! So I think I have to beef up the tabernacle somehow.
Once the mast was up, I could see if the tent poles were the right size to go over top of the boom:
You can see the decktodes are finally being utilized.
This is the boom tent that came with the boat. It almost fits. I'll use it to keep the sun off the top of the transom so I can finally paint it.