Karl, consider this when deciding how to cut the studs. If you cut them before installing them you can easily dress the end of the threads on your belt sander. Not so easy when the studs are pressed into the hubs. If you don't dress the end you cut it will be difficult to spin a nut on the stud. If you use a angle grinder to cut them when installed you are more likely to damage the mounting surface of the spacer depending on the spacer configuration you're using.

Threads are cut on a 60-deg inclusive angle so you can easily dress the the cut end by carefully sanding the rough edge while holding the stud at a 30-deg angle to the sanding belt. I typically use a portaband or band-saw for cutting threaded fasteners or all-thread as it makes a cleaner cut than a cutoff wheel and easier to control. Just a tip from a very old machinist.