Yes, standard tuning is GBE. Also the open tuning chord shapes work for ANY open tuning.
I guess I should make it a little bit clearer.
That's a neat I IV V calculator.
Maybe you could make a slide chart (slide rule) out of it and sell them for a couple of bucks.
Google "slide chart" for info on them and companies that can make them for you, or you can make them yourself.
a slide rule is exactly what it was Mickey