Paint Now or Later?
I painted my RV6 "now" (before assembly) to save money and because of space constraints. There were between twenty and thirty pieces, large and small. Each one needed to be positioned for paint, and to be conditioned, primed and painted. The paint came out OK, I was OK with the process and glad to have saved the money. But it struck me as a very inefficient way to get the job done. I can't imagine paying someone to do it that way.
I had the RV12 painted "later" after I had built and flown it. With the RV6 I was watching my dollars. 15 years later with the RV12, dollars were less important. If you are going to pay someone I would say to paint after flying.
With both planes I had tweaks to do after flying that required paint repairs on the RV6 but that was not a factor with the RV12. Also, I was still tweaking the RV12 paint scheme right up until painting time. I was glad to have time for that because my ideas kept changing.
So if you are hiring the work out I would say paint later.