I see that responded to my question,

in terms of megapixels - well technically 6-8 would be fine

Yeah ... that rules out my Nikon 4300 w/ 4.3 MP.  That's about the advice I expected to get. 

Somehow I don't think that my Canon A-1 35mm would give me quite the image quality needed. 

OTOH, I have a medium format 6X6cm (or 2 1/4 square, if you prefer that name) film camera -- I could shoot 120 (or 220) film and scan to get either 60 MPx or 90 MPx ... but the lab wants a bit of money for a scan at that level of detail.  $15/image if 60 MPx.  That means if I shot a roll of 120 for each of the 4 classes, it would cost $900 to scan the film ... or that could convince me to buy a DSLR wouldn't it??? ... For that matter, at those rates, I could almost justify buying a new toy ... the Nikon Super Coolscan 9000-ED for about $1900 ... it would handle these film formats ... 35mm, 120/220, 16mm, 6 x 7, 6 x 9 film at 4000 dpi optical. 

I could use the Nikon 4300 to shoot backup images.  But the camera positions would probably not be the same.  There could be perspective issues between the digital and film cameras. 

What do you think of that Idea? 

--
Martin

p.s. Thinking about these costs is making my head spinn ... must sleep on it. 

p.p.s. ... and this is a hobby???