Good Evening, Mainecooniac,
After using rotary processing for about thirty years and experiencing virtually no problems with it, I can offer nothing based on scientific measurement or experimentation, but from the extensive experience, I can suggest the following in response the last Jonnielvis post:
1--My Beseler motor base (it's nonreversible with only one constant speed) rotates my Chromega drum at a rate of about 20 RPM, which I would guess is considered fairly fast; I haven't used any other motor base so I can't make any comparisons. I do a manual reversal after the first minute and every thirty seconds thereafter. I have never seen any failure to remove the anti-halation backings from film. I do only 4 x 5 film and have the ribs and the spacer in place to keep sheets secure; perhaps this helps randomize the circulation during processing.
2--I always use a water pre-soak for about 2 minutes; most of the anti-halation coating seems to be disolved during this step, judging by the color of the disposed water.
3--As I noted in my first response above, I'm generous with my solution amounts, but I'm sure that the film is above the solutions at least as much as it is below them. I can't see that this is any problem, since enough solution remains on the film surface to continue acting throughout the rotation.
4--I haven't used the Beseler drum; perhaps there's something about it which causes difficulties my Chromega does not.
5--My film has been predominantly Kodak, but results with occasional use of others (Foma, J & C, a little Ilford) have been just as satisfactory as with Kodak.
I confess that I am at a loss to explain the problems Johnielvis has cited, but I doubt that the drum rotation speed is likely to be a significant factor.