Is there a marine biologist around?

This really really sounds like a case of missing the forest for the trees. Either kill the fish, or keep it healthy. I don't think it's this complicated. If you can't stomach killing the fish, then let it go.

A bass drowns out of water just as you would drown under water.....

Suffocate would be a better word. Their oxygen extracting organs (gills) are not drowned in anything whereas our lungs would become drowned in water if you were to breath it in.

So totally variable.

But if you plan to release it, you should have it out of the water as little, and for as short a period(s) as possible, keeping it in a livewell between photos, weighing, etc.

Fish

Just get the fish back in asap have the camera ready and wet your hands so you don't rub off the protective slime they have. i hate to see people catch a bass then fumble looking for a camera or a scale