good to hear you are getting your flatness problems resolved Thomas. I do have to ask if you've checked your enlarger alignment lately? I had some similar problems some years back and sound my Beseler 45 had slipped one of it's cogs on motorized lifting mechanism. I was lucky that I have a versalab enlarger alignment tool. I could make prints that were sharp for the most part. Since I fixed the issue and fine tuned the alignment with the versalign, that it's a breeze now to print. I also replaced many of the old tired screws on the MCRX-45 bracing rods with hex head screws that allow more torque. I have not had to make ANY adjustments since doing that. I'd gladly swing over and help you check that??
After I realigned mine, sharpness improved greatly.