Always use new cutters that have never touched metal. Polycarbonate needs a very sharp edge so use uncoated carbide, preferably the micrograin carbide with a highly polished finish that is used for the cutters used on aluminum.
24,000rpm is a bit high so if you can back it down to 15,000rpm that might be better. Read below, keeping the chipload high enough at high rpm means the feed has to be high which can affect accuracy for curves and sharp corners.
Keep the feed high, something like three times what would be used on aluminum which translate to around 8 to 10% of the cutter diameter per tooth for the chip load.
A 1/2" high helix cutter should be able to go full width and 1/2" deep because it tends to screw the chips up out of the cut, 1/4" it may be necessary to reduce the depth to around 0.2" for full width but for side facing with an engagement of up to 80% of the tool diameter full depth should be okay.
An air blast is a good idea to clear chips and provide some cooling. For deep slots where it is impossible to get good chip evacuation coolant may be needed. Polycarbonate is resistant to most water mix coolants or a soap and water mix can be used.
For drilling it is absolutely essential to use sharp drills and keep the speed moderate to avoid melting the chip in the hole. Moderate is about as slow as you would drill mild steel but with three or four times the feed.
Good clamping is essential; polycarbonate is flexible and slippery and it likes to climb up the helix on drillls and milling cutters.