The interrupted cut won't bother a HSS tool provided it is rigid enough. If you are worried about the carbide, don't use it - HSS will rough just fine.
Just cut it about 0.003" - 0.006" over sized, then make the finish cut in a single cut. If it winds up oversized for some reason, just grind the tool to a point and you should be able to take a 0.001" deep cut well enough. The height of the boss is not critical, anything taller than about 1.5mm past the chamfer is fine. The boss is just there for alignment, it serves no mechanical function other than that.
Shrink fitting the chuck is certainly accepted by many, so there is nothing wrong with it.
I would actually cut the boss a few thou undersized so I could center the chuck after it is mounted. This is especially good for 3jaw chucks, you can get a 3jaw to clamp under 0.001" repeatably if you got lucky on the tolerance range. After all, a Set True chuck is an just adaptor with some extra screws and a loose boss. Having the chuck loose on the boss might also give you a very tiny margin of safety in the event of a crash.
Just mount the chuck with the bolts lightly snug, clamp a piece of ground rod in it, and knock the chuck around with a hammer to get it on center.
Bison chucks are kinda the standard that other chucks are compared too. It should run very true when shrink fitted.