Hey Kiwiki,
for a hand router or a router table, yes. But not on a CNC: You just need to program and probe correctly 
Alternatively, as you need to put it on a spacer anyway as Darren @CSM already suggested, you could simply use a slightly smaller round piece made of scrap
The radius of the Sistemi Klein convex router bit is 18 mm so a circle with 36 mm diameter (d). Seems to match:
I hope I was allowed to draw my circle on your drawing!
But I would do it with the 8 mm radius cutter (ball nose) as shown above in the video. Especially because the 8 mm radius cutter costs only half the price of the convex router bit and a radius cutter is versatile and can be used on many, many other projects!