i would be grateful for any comments/advice on how to get a client to activate her glutes, without engaging her unbelievably tight psoas muscles ? Obviously we are working on releasing her psoas bit by bit. Any tricks of the trade?! Thank you.

Could you maybe give a little example of what that looks like? Not discounting muscle cues/timing, but it's easier to explain movement strategies based on bony alignment and body position vs muscle activation ;)