> That sounds good, especially mixing the color. Is the putty any good
> structurally, or is it not filling the cracks between the strips? I guess
> the concern is that it might work loose in time.

Its just a filler. The strips should already be secure to each other with the white glue. The structural strength (and waterproofing) is acheived with the epoxy/glass covering. The advantages of a complete putty fill is the elimination of the tiny bubbles that get trapped in the staple holes and small cracks and the water putty is lighter in weight and cheaper than epoxy fill. An epoxy seal coat is still required before glassing.