Want to Buy WTB Dark Slide for Polaroid Film Holder 73C or 405

I got hold of a fully working MiniPortrait 203. It had a half pack of FP100C left in it and now that it's gone I'd like to covert to a sheet film camera. I've cut my own film to fit in there but I lack a darkslide to make swapping film easier.

Anyone out there have a darkslide or holder/darkslide combo? Anyone here can fabricate one?

Thanks!

I have a complete 405 I could sell along with several expired, room temperature stored packs of FP3000B and at least one of FP100C. All the film is at least twelve to fifteen years old, and I have no idea if the pods are still good. Pretty sure it still has the dark slide in it. I'll try to remember to check when I get home tonight.