Honest truth is your machine can not run this cutter correctly without compromising wear and finish. You'd have been better buying more of cheap HSS as they'd be cutting more like correct so will probably last longer and give better finish. Carbide doesn't like being run incorrectly and will wear fast if not.

But to answer your question then a very very rough ball park figure would be find the correct feed n speed. Divide the feed by your max feed then divide the speed by this number. ie 7500mm/min 21,000rpm would equal 7500/2000=3.75 21000/3.75=5600rpm

But again this is very rough ball park figures and trail n error will be needed.