Maybe there's a language barrier here, but of course you're allowed to have a signature. Just stick to the rules I laid out in the first post. (Maximum three lines, no bold or colors, etc.)
I made a signature for you that would be fine, although you should to edit it, especially to add the actual link to your radio show (assuming you want that there.) There might be a slicker way to make you email linkable for booking lessons, but I don't know how. If you do, then go for it.
It's also fine if you want to edit the Radio show text if you want to include something like "Submit your tracks for my radio show" or something like that.
Yes. If it makes you feel better, I've limited some people to one per month. In your case, though, you do have legit knowledge to share, so two is okay.
Problems arise when there are 10 threads in a month, as you did in June. In fairness, it wasn't just you. About a dozen other companies and teachers were also posting tons of threads (almost all with zero replies), so I'm taking steps to slow that down, so that the forum doesn't become abused for marketing purposes.
I'll add that three of the abusers are also advertisers, two of whom canceled their ads in protest, which is fine by me. So rest assured this isn't a ploy to sell ads.