Kinda like yo MOMA. just playing but go to your local dro store. they have heavy duty ones that do 8. i would use them. use only 6 of the air spots if u r rly tryn to max out ur garden.
They say 1 liter per gallon I think. But dont be afraid to give your plants more bubbles .. More bubbles wont hurt your plant but they will like it in the end .. The More the merrier. I use a big ass 12 port air pump 110 liter/minute for 4 plants and it pushes mass bubbles.