I'm glad you weren't dissuaded from the old school try- looks good and thanks.
If you're still game I hope you'll try slitting.
I've done the dark madness with 10 inch film loading to homemade Cirkut spools but I haven't regained my strength sufficiently to tackle slitting.
For 15 ft or so lengths I think I gotta apply the blade between the main film roll and a takeup spool and cut-while-winding. No one has reported trying that method [that I know about, so I gather it's a trade secret or a failed idea, sigh.
good luck