> Hi nancy, to cut the foam to size, the method I used was to first determine where I wanted the bulkhead to be positioned, then using a handful of 3x5 cards, make a ring around one half of the boat at that position,take that floppy template and use it to trace both sides (left/right) use a short cross cut saw and carefully cut the foam, if you feel confident you could angle the cuts to approximate the taper of the kayak,forgot, you can cut the foam undersize to take into account the thickness of the hull. I assume that you've already cut out the hatch and made whatever underdeck carpentry is needed before installing foam.

a surform is good for sanding the foam down. good day