Hi Dave,
With the RapidClear, it was brush it on, then assemble, no waiting necessary, but no harm done if it dries. The purpose is to seal up the joints and end grain of the planks so they don't soak up too much Soup or varnish and get dry. Let me emphasize that this is an experiment, though we expect it to work fine.
When using the 5200, it was used the full length of the garboard rabbet, the stem rabbet to bed the plank ends, and the gains. The advantage to using 5200 is that it is a very effective bedding compound. The disadvantages are its color and difficulty cleaning up squeeze out, and the near impossibility of separating a joint should repairs be needed.
There are other bedding compounds that could be used as well, each has its own advantages and disadvantages...
The book is a little ways out. We have in hand well over a thousand photos to work from. Writing will begin any day now.
By the way, which canoe are you building?
Dan