Sorry for the slow response.
I was really surprised how easy it was to flatten PVC pipe, and also how well it glues.
That GNAL developing reel works great. Time will tell if a 3D printed reel lasts for the long haul, but it was printed in PET-G. I will have to see if my mate can print me a second, see through reel, as there is space in the tank to develop two films at a time.