masterfulmusic29

I have heard the school of the better the instrument the better you will be. True and pro horns are easier to learn on. What it comes down to is if you can afford it and want a better horn buy one. If you are a relitively new player I would recommend a Bb because all the other ones have intonation problems.
The playing by ear thing is hard to explain. Above all don't be afraid to ask your fellow musicians to go over something one more time if you have an idea for something different. Practice at home to try to find something that will sound good with the music.
Good luck
James