I traced the position of the keelson and stem on the underside of the planks, took them off and taped off the gluing area so as to reduce the mess from squeezeout.
As cold as it is, I switched to the 'fast' hardener, installed a new set of pumps to measure proportionate aliquots, and ran through the sequence again. Screwing up at this point would reduce my project to a messy pile of epoxy-contaminated wood. It would be irresponsible even to burn it.
The protocol for glue-up is to coat the mating surfaces with straight epoxy, then mix up up some epoxy putty (some saw dust and microfiber filler) to the consistency of mayonnaise or peanut butter, and apply liberally to assure a joint that is not glue-starved on the one hand (straight epoxy soaking into the wood) and has good gap-filling properties on the other.
The nails contribute little to the strength of the finished boat -- they serve to position and fix the planks while the glue sets up.
V-blocks were attached with a glue gun to some bar clamps and brought to bear on the most forward parts of the planks, pulling these awkward horns flush to the stem. It is hard to be sure with clamps in the way, but it seems like they did a good job. The planks seemed to conform to the frame in an untortured manner.
About 4 hours.