Rear airbag setup

[slick78]

I got a question. I got a 1978 c10 stepside and im doing my suspension. I already did the front now to the rear . The rear is alreay lowered thats how it came when i got it. They took out leafspring and just left the long one and the little one. I wana put bag on the rear tho. What would be a good setup? I have heard of the air over leaf setup, is that ok? What would u guys recommend? And if i put airbags, do i have to add leafsprings?one ladt quedtion sorry. Does anyone know how many inches is lowered the way its setup now? Please help!!! Thanx