what do you mean by later "advanced" big bands? raeburn, thornhill? or really the fifties (kenton, gil evans, something i just forget...)? i was a bit irritated when i first heard george handy (on the zoot sims riverside album, and to a lesser degree burns) expecting something remotely avantgarde... settled the issue for me by thinking that they were not early fifties avantgarde but forties avantgarde... (that said, i know way too little about all these things to contribute anything meaningful...)