I know that you are half way pitching me some shit, and half way inquiring for real why I made the decision to move this here. I will try to explain.
First, I AM a songwriter, producer, musician, etc.....Hell, I posted one of my halfbaked ideas in the Clinic not that long ago. While I am not a balls to the walls songwriter/performer anymore, and spend more time on engineering, I go back QUITE a ways in songwriting. So, please, before I whip out a bunch of songwriting whoopass all over you, don't suggest that I don't KNOW the distinction between songwriting/arrangement issues, and actual mixing issues!
You original question suggested that you had all these "parts" tracked, and that they were different approaches to PERFORMANCE of the parts. Your question pertained to deciding which "version" of the part to keep. Frankly, to me, this has far more to do with songwriting/arranging issues than anything about actually mixing. Yes, there COULD be significant issues concerning HOW to mix these parts within the song, if they are quite different (how they fill the sonic space, etc....) but how can you be advised about how to mix them in when you, the songwrite/producer/arranger HAVEN'T even figured out which part to keep?
To illustrate further, let's say that I tracked two different guitar solo's for a song. Have them both there on the tape (hard drive, etc....). One if very sparce with a lot of space. Very simple melodic structure. The other solo though is very busy and complex. Deciding which to keep is the mixing engineers decision? Not on the projects I have worked on in the past. The producer usually decides that, and he decides that based upon how the part fits the SONG! Once the producer decides which part to keep, it is then up to me to make that part fit in the mix.
So, I felt your question had far more songwriting/arrangement pertinence than mixing pertinence, thus, moved it here, where all these "intelligent" people could help you in deciding....
So, now that you know where I stand, I will add my two cents worth to your question!
I DON'T have an answer!!!
I DO know that when deciding on whether to keep a part or not, I consider the "mood" of the song. If the part is busy, I ask myself "Does a busy part right here help the arrangement?". If it is a sparce part, I ask myself "Does this part say something significant in the song and carry this part?". But only the songwriting and/or producer can really say.
Producing/songwriting/arranging are all seperate, yet, closely related "arts" in music. There are arrangers that cannot write a song to save their ass. There are songwriters that cannot arrange worth a shit! Many "pop" music releases enjoy all three of the above "artists" to make a song fly. Somebody writes the basic song. An arranger is brought in who really makes the arrangment and instrumentation very strong. Then a producer drags the best sound/performances that is possible with the gear and performers. The Producer is usually the ultimate voice in ALL the above issues. He is the guy that has the "hunch" on what will keep people listening to a song and what won't, although he may or maynot be very skilled in contributing to any aspect of the production of the final product. But he is the guy that usually knows WHERE to find the right talent for every crucial part, and can HEAR when that person has stumbled upon greatness in their craft.
So, maybe this is more of a "producing" question. Maybe we need a "Producing" forum! LOL.....
But, I feel this question works better in the songwriting forum, and this is where I moved it. Only moderators of a forum can move stuff out of their forum, so I cannot move this anywhere else. If you have a big enough issue with this thread being here, please feel free to contact this forums moderator and suggest a move to anywhere you choose EXCEPT back to the Mixing/Mastering forum...
Ed