Thanks everyone, this is all awesome information. I'll run a couple more test prints with a lower mesh count, less penetrant (I am using the Rutland penetrant) and a touch more activator and see how results vary.
While we are on the topic of additives, I am also using 3% Matsui Fixer N and 3% Matsui Softner MG which I believe is the max load for both products. Do these sound like good starting percentages for now or would it be beneficial to back off?
I'll report back if testing goes well.