I know weight is an issue for you but I ALWAYS have a beanbag with me. Find something, anything to set it on, and then your camera can be held steady. Plus, if you need to in an emergency you can always eat the beans...

These are really straightforward for fixed focal length lenses, but not so for zooms, especially with the extreme zoom ranges available now for digital photography.

Look it up, the spelling again is scheimpflug (principle)...

First of all, the correct spelling is "scheimpflug." And no, this is not an obsolete concept and no, the PP "approximation" of the effect is only an approximation and not the real thing. When one examines the image produced on a "circle of confusion level" one will find that that sharpness cannot be duplicated by any post-processing means. The only way this could truly be accomplished would be to "bracket image focusing" and then post-production blend the images.

Yes, this I know. We had this available when I worked for Minolta as well. However, the basic topic of discussion was of resolution that makes no difference without the sharpness of image through the depth of field range offered by tilt/shift (that I am sure 99% of photographers are unaware of).

What people who have never used a large-format camera do not appreciate is their ability to utilize the scheimpflug effect that can not be done without being able to tilt and shift the lens board and back.

Sold my Sinar f, ALWAYS regretted that, so mine would be a Sinar P 8X10 so I could tray develop the negs and only need to contact print...

I worked for Minolta for 15 years. Over this time I encountered cameras exhibiting this same issue, though my solution may not help with your camera, it is worth a try. What can happen is that the film wind mechanism gets slightly out of sync with the mirror and shutter.
Remove the lens, open the camera back, gently slip your finger beneath the mirror and raise it up, using your fingers in such a way as to have your finger on the inside of the cloth shutter and thumb on the backside of the cloth shutter, gently wiggle the shutter cloth. This may re-sync the various components. One very specific way to determine if the shutter is out of sync is that the leading and trailing edges of the cloth shutter have a metal strip on them. If when you open the camera back you can see this strip then the shutter is out of sync. Alsoit would usually be more to one side than another indicating which direction the shutter will need to be moved. Doesn't always work but many, many times I was able to preform this proceedure and hand back a working camera to the owner.

Too bad they didn't have the "BIG" flag flying...

Just saying, that was what the technicians used when cameras came in...

While working for Minolta many years ago, I was taught a very efficient electrical contact cleaner to use was Hoppes #9, gun bore cleaner, available at sporting goods stores.

What I learned while working for Minolta for 15 years was that heat was the biggest culprit for lens damage. Excess heat in a trunk or inside the car can liquify the lubricants that are used for the diaphragm blades leaving them coated and no longer able to close and reopen within the time period. Activating a lens diaphragm manually while observing the movement was always a test when considering used lens purchase.

I will offer again; while working for Minolta we were taught to only use distilled water (moisture) from exhaling onto the lens and then using a photo chamois that is thin actual deerskin. This was what was to be used cleaning front silvered mirrors as well. To prove, clean your lens(s) with whatever you use and then exhale onto them. If any residue is left on the coating it will show. My technique will not show any residue.

Having lived close by I have often used the preeminent source for answers to questions like this, The Smithsonian Institution. Here is a link that will get you started; https://siarchives.si.edu/blog/panoramic-panic-part-iii, follow it through to the end for additional relevant links that will be helpful.

When I worked for Minolta as a technical representative we were taught (assuming all of the visible dust is brushed or blown off first) to only use the condensation from one's breath on the lens followed by a wipe with a photo grade (very thin) chamois. This was the only technique that truly left no residue as proved by lightly exhaling on the lens surface after cleaning (try this after using any of the other suggested techniques submitted). This was also the only technique advocated for cleaning the front-silvered mirror of an SLR.