I saw Gil Evans just the once - it was with his 'British' orchestra, at Ronnie Scotts. Was sat not too far away from his electric piano. As I recall it, the US musicians brought in included Miles Evans and Lew Soloff. Might have been Billy Harper too but not sure. UK musicians I recall included Ian Carr, Chris Hunter, Don Weller, Ray Russell, Frank Ricotti and John Surman. I think John Marshall might have been on drums. 1983 I think.
They played several numbers from the Hendrix album as I recall it.