Thank you very much for the detailed, helpful clarification.

Quote Originally Posted by Crocodile View Post
The English version implies a polite and respectful request, something like: "If you start correcting my mistakes that surely will only meet my positive response." However, the Russian version means something like: "Of course you might start doing whatever you want and correct my mistakes, and unfortunately I can't do anything about it".
I got the phrase Вы вольны + verb from dictionaries which offered no explanation about tone. Analyzing it, I now realize that there could be various nuances, depending on context and so on, just as with many other phrases. Using this construction, though, I don’t see how any corrections would not be accepted since I asked for them.

So, what you really want to say in Russian is something like: "Свободно исправляйте мои ошибки" (=feel free) or even better "Спокойно исправляйте мои ошибки" (=feel relaxed).
I originally wanted to use cвободно, but found no example that indicated that it could mean “feel free”.