it's not really complicated.
The brakes are typically threaded 1/2-28 (skinny barrels, many AR's or the larger 5/8-24 -( some metric threads available). The can will fit on any of these brakes (same manufacturer) as the outside diameter of the brakes are the same and fit the internal of the suppresor. So your cost is around $1000 for the suppressor (it comes with one brake, your choice of thread), a $200 stamp from the ATF, and $125 for each additional brake. You can move the brakes across barrels, but often they are Rocksett or Loctited to the barrel. While a direct thread can is cheaper, many people prefer brakes, it's a better system if you use your can across weapons. Also, if the threads are cut long (on a direct thread) there is carbon buildup on the extra threads, making suppressor removal sometimes a bit difficult.