If you have a mister or can faricate an air gun for cooling and removing chips that would be the way to go. RPM can be as fast as it will go as long as you can keep the tool cool and the chips out. I use carbide 2 flute, single flute even better. I wouldn't worry about braking any records with the feed rate. Typically you could cut as fast as you want. However with your set-up and machine I'd be real conservative with the feed rate. Figure .001-.002 chip load. This isn't a production job and you'll want the best finish you can get. The material is prone to melting and really gumming up the works so be careful about letting things get out of hand.