I use a 6040 and my most used cutter is also 3mm single flute carbide. However, I turn it from 16000 to 18000 rpm around 300mm/min when I slot up to 3mm depth, and 400-500 mm/min when doing full depth (5-10mm) outside contours. I dont think the speeds you posted first would even work on my machine.

I also think a mister is necessary, I use alcohol because I also have a fan that draws the fumes outside.