You don't get a lot of time to work with foam. You need to make sure your alignment is good. Foam builds up pressure and this could cause missalignment at the worst possible moment. so you're now 5:2 against....What do you think of filling the void between the CR's with 2-part foam to lock the joined area to the motor tube and make everything more solid? It's about 4:2 against in my little poll. I can calculate the volume pretty closely and mix less than needed. You can also apply that stuff in multiple (small) batches, too. It's tricky stuff, but I've worked with it before. Wouldn't it make a nice, solid, well adhered segment that is fully integrated into the rest of the rocket?
Norm