Pyrocat HD for Kallitype Negs

I've been using the 2:2:100 mix as I do Kallitypes. However, the series I'm working on is a still-life with white background and I've been getting inconsistencies in the white.
I had read that this is an issue with pyro, and that Sandy King suggest using a more dilute ratio with longer times and less agitation ("minimal agitation")
I've also been getting a fairly high general stain and understand that using more A solution (reducer) helps reduce the B+F general stain.
So, if I'm now using 2:2:100 at 73 degrees for 12 minutes. What would be my time be for say 3:2:200? Double? And the agitation every 3 minutes?
I would really appreciate any suggestions for dilution, time and agitation.
I should also say that this is 120 roll film. I have been printing onto x-ray dupe film for the enlarged negative.

thanks,
david