I use a 45 degree bearing edge on my drums because that's the Router bit I have. I mostly do a standard bearing edge with some variations here and there. EZduzzit is right, work to make a drum the 1st time and flow with the punches. It took me 4 attempts before I had a shell I could use. I used cheaper Poplar wood because of the trial and error. Of course I should say that I had no wood working experience when I decided I could make a stave shell. Here is one stave shell that is waiting for hardware. Very satisfying when it comes out right.
BTW your shell is going to be very thick at 20mm(3/4") and will sound loud and higher pitched than say a 1/4" shell. . . James