If you're going to have the lab scan your film it sometimes helps to know the lingo:
Most minilab operators will offer two settings for scan resolution: "4-base" and "16-base". "4 base" is approximately 1024 pixels across the
width of the film, 16 base is 2048. (64 base is approximately 4096 pixels across -- if you can get it).
For 35mm film (135 in lab-speak) that works out to
4 base 1024 x 1536
16 base 2048 x 3072
16 base for 6x7 format from 120/220 roll film is 2048x2510 (from the lab I use), etc.
Note that because exposures on 6x4.5 format are vertically oriented, a 16-base scan of 6x4.5 has fewer pixels (2048x1536) than a 16-base scan of a horizontally oriented image format.
Oh yeah, the term "channel" is sometimes confusingly used to refer a particular set of film-response settings for
all color layers.
IMHO I have the lab return film sleeved and uncut; I cut these into strips and store flat (with sleeving) in printfile ultima pages. I suppose that's not exactly grass roots.