Crucial point (part 1)

I am now at the point, in my project, that I have to decide what sound I am going to use. How I am going to use them it was all figure out more or less at the programming sequencer procedure (and still is). This point is crucial because my decisions now will bring the composition alive or not. Bad quality and bad combination of sounds will of course produce a bad composition. In addition to that I have to consider how sound effects in Ableton Live will change the final outcome. It is very similar to cooking a Christmas turkey dinner with the staffing. If the turkey is not good quality whatever you do with the rest of the dish the results will be less than medium. From the other hand if the turkey is free range and good quality, fresh from a butcher, then is more likely to have an unforgettable Christmas dinner. There are two ways to do these tests. The first option, which I don’t have, is to test each sound at the rehearsals to see (hear) whether are appropriate for this composition. In other words buy ten turkeys from different places and put them in the oven to find out which turkey taste better so that you will buy it for the Christmas dinner. Rehearsals in my case are tricky because the performers are doing this for free so they are not so happy to do rehearsal just to figure out what type of sounds I will use. The other part that is also very related to the final outcome of the composition is the Christmas stuffing (sound effects). Ableton live have a wide range of sound effects that I can use but which of those will taste the better?
In addition to all this I have to use 8 different sound files (two for each performer) that the qualities and character of the sounds will be a pleasant mixture. Again like a four-course meal with two ingredients for each course. The reason for this decision to have 8 different sounds files, two for each performer, is because I the composition is in an 8-speaker surround set up. Each performer will have a pair of speakers with the ability to pan and choose the sound file on the fly. The only sounds that I know so far are the alto saxophone and the electric base.

My approach here would be a combination of experiments with sounds. I am aiming for faster and most efficient way to choose between the sounds. I know that I will have base and saxophone so having those two sounds as a given I will start choosing my sound around that area. I am approaching the sounds as a saxophone quartet with frequencies low middle and high. I will update this as soon as I decide what sounds I am going to use.