Recessed lensboard and bag bellows is a must. I have a recessed Toyo-Linhof adapter, then had my 65/8 SA on a recessed Linhof board.
It was an absolute bitch to work with, cable-release didn't fit in the recessed lensboard, very fiddly to change aperture/speeds, and on a Copal 00 shutter with no preview I had to use B to focus. Then the only cable-release I had that fit the recessed board fell out and got run over and the plunger wouldn't lock on B to focus anymore. I couldn't find another in the hundred at the camera shop that fit the recessed board so I hardly shot it since.
It did get to infinity, just. But you get zero (and I mean zero) movements.
For filters, the centre-filters are actually cheap enough (<$100) and steps from 49mm to 58mm.
Don't put on a 49mm filter, or even 49-52mm step ring and 52mm, I think that's what I did in the first sample.
This next one was with the centre-filter, no vignetting. The smearing in the top left isn't softness, I think it's a bit of tilt and swing (the other three corners are sharp).
Also, it's wide. Wide. Don't get the front of your monorail in the shot. As for contrast, this is RVP50, colour-calibrated scanner & screen, no digital enhancement (the chrome looks the same as my screen).
Not the sharpest LF lens I've got (that would be my 90mm Fujinon SWD), but this crop of the above shows it's definitely usable at 'sane' levels of enlargements (you could easily get a 16x20 from a 4x5 without seeing any softness). This was a 3200dpi scan, cropped to 1200x1600 and shrunk to 600x800. There may also be some diffraction softness in here, I stopped down a bit to blur the waterfall and it may have been at f/45, it'd be sharper at f/16-f/22 where I normally use it.
Now that I've got my travelwide, the 65mm f/8 SA is on that and never ever ever coming off. No need for movements, barely any need for focussing (and not needing to focus means the centre-filter can stay on permanently too), no recessed lensboard needed, normal cable releases fit in fine.
