Doug,
I had the same problem w/my omega B-600. I shot some B&W 4x5 exposures of a flat white wall using the negatives to create a neutral density filter and cut and inserted the 'filter' in the enlarger. Exposure times are now up around 4 sec for Ilford MG IV satin and about 8 sec for MG wartmtone glossies.

best regards

john