Yes, I do think my motor base was just a tad off level and that's probably why the corner didn't get developed. But I figured more solution would help maintain the temperature better too, and that's definitely a concern because I want consistency and repeatability.
I'm printing 8x10 from 4x5 so I'm not enlarging the grain much. But I don't have any problem focusing black and white.
Yeah, if I went to trays I would develop at a much lower temp, but that temp would be very well controlled unlike my current drum arrangement. I haven't actually tested it but I'd guess its far from optimal. I expect that I will eventually move to 4 bath processing but I don't see why that would be a problem.
The only thing that might stop me is quality. C-41 must be done at the higher temp for best results. Does that apply to RA-4 as well? Anyway I'm content with drums for the immediate future.