When I am calbrating an unknow film (and I do this semi often - on found films in bulk loaders I buy, etc). I expose them to a reflective step wedge test target in a copy camera, to determine the minimum effective exposure to overcome base and get image content off of the toe of the H-D curve.
Then a transmission step wedge is useful.
I use the step wedge in a slide copier where the light source is daylight to fine tune developer times.
For reversal, thiocyanate into the first developer has always worked best for me to get rid of the overall grey haze.