You'd be surprised just how many venues there ARE for original music...
Now, admittedly, until you are signed, you either got to have a LOT of fans or lots of thirsty relatives before you are likely to make much money playing these joints!
But the thing is, most of these places are youngsters' hangouts. You've got to REALLY be interested in new music before you are ever likely to go to one... But you'd be surprised at how willing some of these young songwriters are to collaborate with older players who are willing to be simpatico with their style, and help them get more polished demos.
It's a lot of fun, and brings a certain air of legitimacy to your arranger use. It isn't JUST for playing Blue Moon, or In the Mood, y'know....
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An arranger is just a tool. What matters is what you build with it..!