Thank you, very helpful as usual.
I understand that Sinar markets F3 as a sort of a field camera and it is impossible to use the F3 with the Sinar-M and without a sliding adapter.
Sinar recommends p3 for Sinar-M users. Than again a question, what is the P3 camera? I guess that a lens board with a lens, a bellow , a rear standard (or a Sinar-m shutter without Quick Clamping Adapter m) and an electronic interface from lenses to a gidiback constitute a camera. The rest, under the camera, is the mechanics to support the camera and provide the movements. If I have the standards, the lens (+shutter) and the back I have a camera. Sinar-m on a p3 is a smart system for studio work, I just wanted to explore options to find or to build an outdoor t&s camera on the base of my Sinar-m. I understand the limitations, but I remember that there were several photo systems with bellows between lenses and film.
Sinar -M is a modular camera and IMO my idea of a short bellow between the Sinar-m and the lens is not so crazy. CAB lenses and the sinarback will be connected thru the Sinar-m.
I am not a pro with a lot of everyday experience, but I am fond of shooting landscapes on 54 and 13x18 film and I think that sometimes some tilt could be useful. I use an ALPA SWA with shifts, and if I need sharper foreground I blend two images. That is why I asked the question: how to tilt outdoors?
I understand that you find the Silvestri Flexicam less intimidating than the Sinar p3: they are not at all the same cameras for the same purposes. The Sinar p3 was designed for studio work, a re-design from the p2, smaller, a bit lighter, but with the same gears and movement possibilities.
The Flexicam is designed for location work, essentially.
If you want to compare, then you should have a look o the Sinar f3, the re-designed model for digital from the Sinar f2 4x5" field camera.
About CAB lenses: no, these lenses cannot be used without the Sinar p3, directly on the Sinar m.