The "best" score is the one that shows you the clusters. It is the one that has 14 staves, not 2. It is the one that proves Gil Evans didn't just arrange jazz; he orchestrated the weather.
If you are looking to master the Gil Evans sound, these scores are essential: gil evans scores pdf best
While primarily a print publisher, they offer digital preview options and authorized digital delivery for specific institutional clients. The "best" score is the one that shows you the clusters