I'm not entirely sure of the technology of the film used, but it could well be ortho, despite it being done at some time after 1955. Of course lith film and the like is ortho, isn't it? I would have grave doubts as to the actual need for 16 bit, but I was determined to scan in RGB, then jiggle the channels to get the best result for the final monochrome end result. The awkward bit is the usual issue of not knowing quite what you've got till you get there, and having to be prepared for all eventualities. I'm not overly keen on carting a V800 about, or for that matter I'm not that keen on paying for one, but as its for a charitable institution that I'm a trustee of, we are generally expected to be self funding for special projects (and I do personally want to get my hands on the drawings to build a live steam model of the subject of the drawings). I have seen these drawings myself, but it was quite a few years ago. I have a memory of them having a slightly brownish tinge, reminiscent of the dyeline copy negative film we used for architectural drawings. This could be faulty memory, though, it was at least 15 years ago.
That said, we sort of broke the self-funding rules recently, on our trip to Sierra Leone, as the cost of the trip came out of the very substantial donation by the couple of British folk who gave enough money to complete the re-roofing of the museum in SL. We had to take it there in cash, and it was rather urgent! Converted to Leones at 10,100 per pound sterling, it was a very big pile of money...
Out of curiosity I just did the nearest to a 5x4 scan I can do on my old Canon 8800F scanner, which is about 70mm x 125 or so. I did that in 16bit mono uncompressed TIFF, and the file was around 615MB. Hmmm...