The mini 6x12cm camera would be a small/lightweight (3-4 pounds) 4x5 capable of accepting a Horseman (or similar) 6x12 roll film back. I'll never shoot FF 4x5 because I like wider formats. Proposed lenses are 38mm SA XL, 58mm SA XL, 90mm Angulon (late model), 135mm f/4.7 Xenar, 200mm Nikkor-M, and 300mm Nikkor-M. I want a full compliment of lenses. I might throw in a couple of the old Polaroid macro (flat field copy) lenses... maybe a 50mm and a 135 with a shared shutter. I don't need much excess coverage because I'll not be using any front movements and only rear swing/tilt. I "might" occasionally use shift to take a second shot to stitch a wider image but this will not be very often. I consider the limitations of some of the selected lenses an acceptible trade-off in order to decrease bulk/weight.
The camera for making stitched 5x12.5in images would be a Canham MQC 57 (5.7 pounds) with a modified rear standard that has greatly increased shift. I've already discussed how this will affect rigidity of the camera and its solution with Keith Canham and I'm okay with what I need to do. My reasoning for using a 5x7 and shooting two images to stitch them is, once again, to save bulk/weight. Proposed lens kit includes 110mm SS XL, 150mm SS XL, 210mm Apo Symmar-L, 300mm Fujinon-C, 450mm Fujinon-C, and a 750-850mm I dunno yet but it must be small, coated and shutter-mounted. That last lens will require a long hat-type extension because the Canham bellows stops just past 600mm. I don't want a tele because they're so heavy. I can store the smaller lenses in wraps within the hat so (in theory) it won't take up much additional space. I might add a 50mm and 135mm macro lens set with shutter (same as in the 6x12 kit) but I would only shoot single sheets for macro work. I know the 210 listed is only spec'ed to cover 312mm but it will definitely cover the 325mm format with no issues. As with the above proposed kit, I won't be using any front movements... just rear shift (to reach the intended 12.5 inch width) and rear swing/tilt for DOF control... so all these lenses will easily cover. Since I'm only shooting landscapes I can live with distortions created with swing/shift DOF control.
As you can see, the 6x12cm kit really won't be that much lighter than the 5x12in kit... maybe 3-4 pounds. I'm just guessing right now but I'll look up actual weights today. There isn't all that much size difference either, IMHO.
I could lighten the 6x12cm kit by replacing the 38mm and 58mm lenses with a single 65mm f/8 SA and by leaving off the 300mm but I could do a similar reduction to the larger system.
Regarding film holders: I would only carry one box of film with four holders and reload in the field. It seems to me that this film/holder package isn't all that much larger/heavier than a Horseman RFH and a half dozen rolls of 120 film.
I guess I'm really asking if anyone has better suggestions regarding each kit. If I opt to build a 6x12cm kit it must be MUCH smaller/lighter or I'll never bother to use it due to reduction in overall quality when compared to the larger kit. I can certainly live with this reduction but not to save only 3-4 pounds of weight.
The changing light and moving objects issue does concern me a bit and I've given this conderable thought. I'll be shooting as quickly as is practicable and overlapping the images enough to (hopefully) work around these for the most part. I do know that wind blowing objects and clouds is often not very cooperative in this regard.
I won't be taking any hand-held photos... it's all landscape work with a tripod. I know I can get by with a smaller tripod for the smaller camera but please remember that we're still just comparing a small/lightweight 4x5 with a small/lightweight 5x7 so there won't be much difference in the tripod either.
Forgot to mention... these will be scanned on a modified Epson v700 (no glass in the optical path) at high resolution and printed commercially on a system that exposes the paper via a digital light bar on wet process (conventional) paper. Print sizes will vary from 10x20 inches up to "rarely" 60x150 with 20x50 being the average.