Most PCB shops don't use the "Chipbreaker" style router bits. The "Diamond Cut" style is much more popular by a factor of 10 to 1. The variety of sizes is also more generally available with the "Diamond Cut" style. Another benefit to the “Diamond Cut” is that they can machine carbon composite materials much better.
PCB shops in the US use a 3/32"(2.40mm) bit and can route a stack 3 or 4 deep assuming the individual board thickness is .062 (1.60mm). A 1/16"(1.60mm) bit can be used to route a stack 2-3 high. 1/32"(.80mm) and .040(1.0mm) can be stacked 2 high. Keep in mind the board shops are using production equipment with high speed spindles and stable granite bases that help with accuracy and lessens tool breakage. Most breakaway arrays tend to based on the 1/16"(1.60m) tool path, of course that is stateside, the European shops may differ.
Generally you are also better off choosing a “Fishtail” (FT) end style as well. They tend to be a little more forgiving if you haven’t set your Z depth correctly and they cut a larger vacuum path.
http://mctinfo.net/router-bits/cat_20.html