A pity we are half a globe apart. I would love to be able to play blues, but have not grown up with it. I prefer playing by ear, but understand notes too, of course.
Must examine what you are telling me here!
I have a mandolin too, but have not played it for many years. Dug it out recently and the metal holding the strings had broken. How? It slept in a very good case, so how? Never mind, I got new strings to put on it, and a new piece of metal, whatever it is called, to screw on.
Have not done it yet, as summer is coming fast here (guess where I live!), and the outdoors has to be tended to first of all, as everything is growing very fast.
I have a bluegrass mandolin book with both notes and TAB from way back, and learned just a few pieces. That was before I moved to the country, with lots more outdoor jobs.
The book has a RECORD with it, a floppy one, that I can't play anymore, but I think I put it on a tape as well.
Tape recorders were good, you could easily play tunes in, and edit them too.
You make me feel like getting the mandolin out now, but I can't! Have things I must do.
SOON!
Could you please tell me exactly the note names with that 4th added to make it a blues scale. Any key will do

- if it is not too much trouble? Sometimes I hear these blues in my head, but when I get to an instrument they are gone. That is where music books come in handy, but it is a bit bothersome to read notes......
Pentatonic.