Register to a P.R.O - ASCAP vs. local P.R.O (Gema)

Hi all, I am happy to have another major label release in the pipeline for this year and it’s time to register for a PRO for me.

The German PRO (Gema) is pretty unflexible. Especially I cannot decide if I want to register a certain song or not. All my musical output will be claimed by Gema automatically, which can be a problem, for example for my past clients who bought a license “PRO-free”.

What is your experience with registering for ascap from a non-US location?
How does ascap transfer payments to overseas?
How is music registered to ascap (do composers upload songs)?
Could PRO-membership generally have a negative impact on my sales on Envato?

Thanks a lot for any comments!