I've spent a fair amount of time trying to sort through this subject.
I use a light yellow filter most of the time (K2 I think) and it usually gives "realistic" results, overcoming B+W film's oversensitivity to blue light. I habitually use ...
On overcast days I often use the clear filter for a little extra speed and since gray skies render about the same regardless of filter color.
One more observation- longer lenses tend to "need" stronger filtration than wide ones. Using the orange filter on very short lenses will usually give very dramatic effects, not my taste, so I never use that with lenses that give a perspective wider than 28mm or 35mm equivalent.
One last note- I cut my medium format teeth with a Mamiya c330 and 55, 80, and 135mm lenses. I found that using a hood is imperative to avoid flare problems, especially with the 55mm. I scrapped my step up rings (nearly all my gear uses 49mm too) and bought 46mm ones and factory hoods. I feel it was worth the expense and extra stuff to carry around.
I hope this proves useful.