I don't have the URL to hand, but of course now I'm going to have to scour the internet for everything I can find about servicing a Widelux. I'll reply soon with something useful.
Plus I'll have to sell my Rolleiflex to pay for it!

Cheers John, yes I can service it myself - I saw a good website recently that shows you how, in detail. It's also a good incentive for me to learn how to do that textured paint finish.

Good spot, and thank you because I just bought it. The Dude abides. 😊

Perhaps your Leica is having a similar problem to the one my IIIf had when I first reassembled the shutter? It's explained in this Instagram post (if the link works):
www.instagram.com/p/BROc5exALIY

I've found a way to run 35mm film through my Mercury I, and the biggest issue in using it is shutter lag. It takes a good half a second for the gap in that big metal disc to spin round to the shutter gate. No good for capturing action.

Good camera, the FED-2. Feels right in your hands and has a wide rangefinder base. I kept mine and got rid of the Leica IIIf, because the FED was nicer to use.

Frame number clarity is a good point. I might have to stop using Ilford 120 films in red-window cameras because I keep skipping frames due to the numbers being so feint.

Mine is on the to-do list. It wouldn't wind or fire when I bought it, but I did the usual idler gear job to fix that. Then added a schottky diode so I could use an SR44 battery. I was delighted, until the meter stopped working after half a dozen frames. 😕 Probably just a duff connection somewhere.

I've taped the incident dome of my L208 so it stays in the reflected position. It's a nice little meter, but I wish you could lock the ISO setting.

Are you worried that a security officer will refuse to hand-check? I have visions of shooting lots of film abroad, and them grinning as they put it all through a CT scanner and obliterate it. Last time (Italy) I bought the film out there and posted it home before leaving. Expensive though.

Easy enough on a 35mm SLR, but rather more tricky on a Hassy. Ideally you would use the older type film back (with a peephole), remove the film holder, place the comparison screen inside so it's resting on the rollers, and view the split prism through the peephole.

You'll need to get another medium-format focusing screen (ideally split-image) and position it exactly on the film plane. Then you've got a datum for comparison, and you can shim the camera's new focusing screen to match it.

Can you find any fleamarket cameras that are long dead but have a 620 spool in them? I've often bought cameras with pocket change just for the spool.