If you wear bars you'll have to wear the shirt that goes with it - in this weather the wet patches under your arms are going to show really well
Leave the uniform to the professionals. Like others I have to wear them when flying professionally. When I fly for myself it's meant to be as a hobby and fun - so you wear what's comfortable.
For your own self esteem and confidence - don't do it! The minute you screw up in your first 100 hours of flying (and you will) then any semblance of sympathy anyone might have is going to disappear when they see the epaulettes, and be replaced by a lot of snide remarks.