Well Flute its discouraging as hell to have someone tell you you're doing it wrong when you've tried so hard to do it right. From your post I don't think the criticizer has even heard you play yet which is not a good basis for reasonable criticism. It also seems as if you started out being there and listening to the session a few times before you even played so you know what kind of music they play already. So I'd consider him a control freak trying to get you under his paw before you've stood on your own two feet. I'd suggest you respond to this aspect of the situation rather than taking to heart any of his comments. You can spend your whole life, if you're not careful, desperately trying to play it right by someone else's standards and that kills the basic reason for playing music, which is communication and enjoyment.