The plan has been donated to the forum...You can get a copy from there, or directly from me, where I can also provide the build pics in convenient digital folders...
I've done a number of experiments using HK matt clear film and it takes paint well without any pretreatment.
After spraying I removed the film from a test frame and scrunched it up to see if it would flake. It didn't so I'm hopeful that it will be OK. The backstop will be Prymol.
Also, for those who enjoy Scroll Saw Therapy, the parts are available from me in PDF form, all ready to print out in an A4 printer. (Note: always check the printout outs against the plan)