Robo...on your queen marking video, aren't you using a Tester's Enamel paint pen? Is there any issue with toxicity?
Now who could have put that idea in your head?
I honestly don't know, I used them for years without any noticeable issues. I did switch to Posca before the whole toxicity issue was bought up because they control the paint flow better. The Testor's would easily drip puddles of paint if you weren't careful. This year I switched back to the numbered disk with non-toxic glue. I could never get them applied right when I used the cylindrical tube with plunger to hold the queen. Now that I hold the queen in my hand, the disk work much better. Ultimately you need to use whatever you feel comfortable using.
I notice the Posca is non-toxic, water based acrylic. Also, have you noticed any difference as far as adhesion or durability?
I have not had any issues with Testor or Posca. I have had some queens with original markings up to 3 years. Probably would have gone longer, but I replaced them.