I'm glad to see that you agree, Alice. How could I express it more emfatically ? it is WHOOOOLEEE WOOOOOOOORRLDDDD of difference ! I regret so much to not having studied when I was 20 !
I would recall this phrase of yours, which I think is very important: "The best teacher is one who has lots of personal experience as well as the knowledge. "
One last consideration: I respect every singer who doesn't want to take classes with an academic singer for one reason or another. There are many excellent singers who reach deeply in the audience's hearts with just a small voice and intimate style. But see that they will never FORCE their voices up or down.

Another last: in fact, my teacher told me: "Don't play the MACHO, you are a tenor, like me" :))

Yours, Andrés Magré