You make the tapes with excess lenght, then when you fit the curtains you adjust tapes/spindfles to position the curtains.
I make shutter curtain material and supply it to a leading US repairman, he's recently restored a 7x5 Reflex Graflex for a Chinese collector that needed 8" x7' of shutter cloth I've some left here in the UK but a large quantity in Turkey which I@ll bring back in about 3 weeks
Yes the slit width governs the speed, you'll need to judge what tension is going to give a consistent release. I found you could get teh shutter working with one blind to start with.
My shutter's working fine outside the camera but I need to change the thickness of the tapes, if it's too thin (same as the curtains) they dont wind up enough.
I'd expected a sunken mount TTH Cooke Anastigmat in the post yesterday or today, as soon as that comes I'll be finishing my Ruby Reflex. I've no lens boards but I'll make new ones, I have a TTH flange that may be the correct size. I've made a new lens-hood/flap, although I did find one on Ebay with fittings from Romania for £3.10 but as I've recovered the complete camera I decided a new one would be a better match. Then I can turn my attention to my Ensign Speed Rol-film reflex once it's finally completed.
Meanwhile I've parts for two whole plate cameras that I picked up at a flea market and more parts and two TP shutters on the way !!!!!