Well, I am new to traditional archery, but a longtime bowhunter/shooter. As for practice, I do some of everything that has been mentioned. I don't do any of them as well as I would like to, but at least for now, I can blame that on being new to instinctive shooting.
I don't understand how a person can be a good shot during one type of practice and not at another though. To me, a person who can shoot accurately, should be able to shoot accurately regardless of whether they are shooting groups at known yardages, stumping, one shot from unknown yardages, or otherwise. If you concentrate and put forth the same effort on each shot, I would think that accuracy would be the same regardless of practice routine.
I do think that practicing in various different ways can only server to better your accuracy(IMO).