From what I've seen at the pattern board, a given amount of choke will nearly always pattern predictably, and by that I mean within maybe +/- 7-8% of what a (choose one) IC/M/F choke should be. That makes it pretty easy to ream and call the job done. There is the occasional choke, however, that does not play by the rules and that will consistently print a pattern you would never predict.
If you don't pattern ahead of time, you pays your money and takes your chances. The other option is to have the smith do this for you, then ream and pattern, ream and pattern, but few people will tolerate the cost.
