I'm waiting for epoxy to cure so I've got a bit of time to post a couple of pictures of how I built up the coaming assembly. It differs from the description in the manual in that the coaming is not permanently attached to the deck at this point. That results in a neater assembly with less sanding at the cost of a bit more waiting time. But since this can be done before the hull is glassed, there can be a net decrease in overall build time. I did this while waiting for the tacks to cure before removing the deck-to-hull stitches.
The first picture shows the initial setup. The string is used to mark the boat's centerline so that the coaming is properly aligned.The polyethylene tarp material keeps the spacers from bonding to the deck. More tarp material keeps the cockpit free of drips.
Once the fit was checked, the spacer top was painted with epoxy/woodflour mix and the second set of spacers was clamped on with a total of 18 clamps. After the assembly cured just enough to hold together, the top of the assembly was again painted with epoxy/woodflour, the coaming applied and clamped, then left alone to cure for 24 hours.
When the clamps were removed, the coaming assembly held the shape of the deck, even when removd from the boat. Now it can be easily sanded, the fillet applied while visible to the builder, the coaming edge rounded, etc. Once the assembly is all sanded and finished (and the deck glassed), it will be glued onto the boat.