So a basic bread recipe might look like (off top of head, not sure if these amounts make any sense)
100 Bread Flour
I know the flour is in weight ounces, but often times in side-by-side recipes I see the water converted into fluid ounces (8 ounces of water equaling 1c). I know sometimes it just so happens that they're the same, but with water that is not so. 1 fl oz water ~= 1.05 av oz water. Close, but off by near 1/2 oz by the time you add 8 of them.
So which do bakers use with fluids? Do they use av or fl? Should I expect to be able to weigh my fluids along with everything else or do I need to convert to fl?