Nash
I use a old Leaf Valeo 17wi attached to an old sinar p, with bag bellows, film era lenses and a Phase flexadaptor sliding back, to photograph product and fine jewelry traditional images. It produces excellent images and am still amazed how good the files are. The movements of the sinar p are much greater than any tilt/shift lens can achieve and combined with the image circles of the older film era lens. like a 150mm Schneider Symmar, a 72mm Super Angulon xl, I have never been limited by shifts or tilts.
Focusing is not a problem as I have a technique that works with all studio camera with 'self-locking knobs', like my sinar. I use a loop on the groundglass for the first focus. Take an exposure and in Leaf Capture, I use the small 100% window to check my point of focus. Lets say I am photographing a soda bottle, so that would be the middle, most forward part of the bottle. If it looks a touch soft, then I move the 100% window on the same exposure to the edge or side of the bottle. If that is sharper, I have back focused and then i would turn the focusing knob on the camera back by the smallest amount (like 1/4 of a degree), just slightly moving it and do another exposure and check both spots again. Often I achieve focus that easily. If the side was more out of focus than the front that would mean that I have front focused and move the focusing knob forward ever so slightly. This is so simple and quick compared to opening the lens and sliding the groundglass into position and refocusing that I never do that anymore. I have a Live View dongle with the Leaf and it is faster and easier than that. Sometimes it might take few more adjustments than one but even that is not that much trouble but you should start with a reasonably focused image. It doesn't work very well with a completely out of focused image. If doing a page of jewelry, after getting the center in focus, I would use the 100% window to check the four corners. Overall, on a product that has been produced, I am in focus when I can clearly see the dot screen of the printing of that product.
Brian