Let me make something clear: I don't care if he is a pro or not. The advice he gives is spot on and he is doing something for free that he could be getting paid thousands for. That's all that really matters.
However, I will say this. I have met Ron Avidan personally and asked him about gh15. He was quick to change the subject, didn't drop a name, but did in fact verify gh15 as a pro. Gh15 has mentioned Ron several times in postings. They are obvious aquaintances to some degree and Ron is an honest man. If he says he a pro, that should be all the verification yòu need.