For a negative to print the same on the same grade of paper when comparing a condenser and diffusion enlargers, the negatives need to have different density ranges. Because of the light is more parallel with a condenser, a greater portion bounce off the film grain effectively increasing the contrast of the negative. This is called the Callier Coefficient. If the manufacturer has only one set of development instructions, they are usually for diffusion enlargers. So, if you are following the instructions and using a condenser enlarger, you are over processing. I don't believe this is the complete answer as to your situation, but it probably plays a factor.
Originally Posted by kbrede
This is a chart from Photographic Materials and Processes that compares the required negative density ranges for different paper grades printed in both a condenser and diffusion enlarger.
LER and NDR chart.jpg
There is something you wrote that is somewhat puzzling, " Even with a strait #00 filter, the darks would build up in seconds, before the highlights, and that was stopped down to f/22 and f/32 on the enlarger." Is there something about the f/Stop that you believe is significant? I think there's something in this sentence that might help solve your problem.
Have you tried making a print without any filters? What about making a printed using graded paper? Maybe your processing is off with the 120 film. A simple test sensitometric test will tell you what you're getting. BTZS explains how to do it well enough to achieve something meaningful. You can also read one of your negative. If the density range should match the paper LER and you're still getting overly contrasty prints, then it can't be the processing.
The problem here is that what you are experiencing, too contrasty with 00 filters, seems to extreme if you are correctly doing everything you say and based on your positive experience with 35mm. I think we are missing a few pieces of the puzzle.