For something to be called a success, it must have results that meet or exceed the pre-established criteria. If you list your criteria, and then show us the pix from a shoot, we could probably help you determine whether or not the shoot was successful. Whatever we on the forums might tell you about how many keepers you should have will not really help you. 1) You need to state your own criteria, and not give too much importance to anyone else's, and 2) Anything we say will just be opinion anyhow.
I don't shoot a ton of staged people photography, but when I do, the number of photos I hope to get will vary greatly depending on, well.......what I want to get. This can range from one to many. However, if you at least make every shot a likely "keeper," then all that is left is finding the one with the best of the minute variations that occur between shots. (Wind blows and then stops, expressions change, etc.) In other words, don't even take the picture if you don't think it has a chance to be a "keeper," and damned near all of them are "keepers." All you have to do is pick the one with the details that you like best for your intended purpose.
I just talked to my ex girlfriend yesterday. She is a big muckity-muck photo editor for the AP with about 15 years combined experience between Allsport, Getty, and AP. I was talking about shooting journalistic pix for weddings, and how I keep about 50% of my pix. She said that in the film days for wire services, 1 or 2 pix that were worth being transmitted out of a roll of 36 was considered good solid work in a news situation. Now, with digital, she says over 90% gets trashed. However, this is in news/sports situations, in which each picture only happens once. If you are doing a staged shoot, I think you should have very little waste that is not caused by technical flaws. You have all the control in the world to get timing and composition right, so everything should be close to right on in those regards, IMHO.