how to you wacom veterans use the pressure sensitivity with photoshop? is there any standard set of variables to control with it?

I use the defaults in OS X, which is for pressure to control the brush size. This works very well for cloning. Once in a while I will switch pressure to control opacity, which is useful for painting on a layer mask if you are trying to finesse and adjustment layer.

EG select a region you want to darken

add an adjustment layer with the relevant area masked in

paint on the layer mask using variable opacity and the airbrush tool to finesse the area the mask applies to -- very like burning or dodging