How do you a gal?

That's a nickname for "girl", like "My gal Sal" (SALLY)

G.a.l. means get a life.

Neither. 2 gal 8 pt = 3 gal

I believe it would be impossible to carry any water in a pile.

5 gal = 4 gal 4 qt 4 gal 4 qt 3 gal 3 qt ------------- 1 gal 1 qt