Also keep in my mind what sized venues you'd be playing, even at some of the bigger venues I've played at, you won't need a 100 watt tube amp. Granted I don't play metal, I get by with a Peavey Classic 50 and haven't had to go past 4 (out of 12) on the master volume.
It kind of comes with time, especially if you play in a certain key a lot. I can fiddle around in E pentatonic or E mixolydian pretty easily without looking. i never specifically practiced it, like above it has to do with muscle memory and just being used to playing it often. Chords are a bit easier especially when you're doing basic open chords which I use quite often when I have to sing a song.
Actually music teachers get payed a butt load of money especially if you work at a college. when I was in my music theory class the teacher told us if you get a degree in music theory you won't have to work for less than 32 dollars an hour for the rest of your life. (due to you could give lessons, if anything).