I have become use to determining development of the film based on the brightness range of the scene. A spot meter certainly helps me to get those readings, as sometimes I can not walk up to them. I develop the negs to fit what I consider optimal contrast for how I make my carbon tissue, or if I am developing negatives for pt/pd printing, I aim for a negative contrast that requires no contrast agent in my coating mixes. So when my Pentax spot meter reads just above "1" in the shadows where I want info and the highlights read "9", I think, "Alright! I won't have to bump the contrast up much at all with this neg!" Quite a bit different than one's needs with roll film.

When using roll film (120), I usually use a Luna Pro SBC and go with an average reading unless the scene has significant info in the shadows or the scene has more contrast than normal, then I will try to take a separate shadow reading. But that is what's nice about roll film, if I am not sure, I can take another exposure one stop in the direction I might be erring on. And I like the sensitivity of the SBC for when one can use a meter the most, when the light gets very low. I think the only time I have used the SBC in incident mode has been copying flat work.

Good luck, I figure that everyone eventually finds an system that will give them good exposures under average conditions and a way of figuring things out when things are no longer average.

Vaughn