Glad you got the PC off without difficulty—as a general rule most plastics prefer to stick to themselves more than the metal of a tool, especially once the tool is cool. Therefore once you get them started they'll come off pretty cleanly. Also, almost all thermoplastics will expand/contract a good bit more than the metal of the tool will, and as an added bonus most are much more brittle when cold, so you may also want to try chilling the tool before trying to knock the welded plastic off.
I'm in agreement with you that feed-rates and chip-loads need to be factored in on a per-material basis in addition to being calculated per tool, and this has cropped up elsewhere in the forum as a suggestion—so I'm considering your experience here as an "up-vote" for that.
Regarding how to avoid this in the future—compared to materials like wood or renshape (a thermoset plastic), thermoplastics like Acrylic,Nylon and PC need a higher chip-removal rate to help pull the heat of cutting away from the tool in order to prevent the plastic from melting and welding itself to the tool, which then prevents future cutting, which then leads to even more plastic welding... which leads to what you have shown us here!
Here's a resource that may help: the basic values in the HSMworks documentation.
And also, here's an online calculator from Monster Tool for feeds and speeds
For the 1/8" tools cutting in Polycarbonate, you'll want to have a chip-load of 0.002-0.005", or 0.002--0.003" for the 1/16" tool, so using the chip-load formula that means you'd have a feed-rate of 40-80ipm at 10krpm, or at 5krpm you'd have a feed-rate of 20-40ipm, which should depend on if you're roughing or finishing, and if you're more concerned about fracturing the plastic or melting it.
I haven't cut polycarbonate on my Nomad yet, but once I do, I'll be sure to post my "fine-tuning" and I'd invite others to do so as well!