I'm really sorry to say this, but most of our hackers probably won't make it a habit to look at New Users / Welcome like that, if by any chance a person like you who can test out hacks comes here and makes a thread just for that. I mean I'm really happy that you're putting yourself out there as a long-time web developer and that you're willing to help people out with constructive feedback, but threads like these aren't part of the scope of NU/W. So I'm afraid I'll have to close this.
Of course, you can always ask the creators of various hacks in Emulation via private message if they'd like a beta tester to test their hack. I assume you mean beta testing, but if you mean casually testing them and giving feedback, then another alternative would be to just test out the hacks you find in that section yourself! And then when you're done, you could come back to their thread or the creator's profile and give your feedback there. No fuss, no muss.
Still, I am more than happy to see a person being so kind and open to help from the get-go. I really hope you find your way around the forums! I'm open for PMs just in case you have questions regarding this. Also, if you'd like to make a new thread here, you could say more things about yourself, and threads like this could help you out if you have no idea what to say that's gonna be okay for a thread.