Start one every day... From the Avodart Phase II trials hair growth on .5mg dutasteride was similar to (some say marginally better, but that is debatable) to finasteride. Might as well start with a dose shown (more or less) to be at least as good as what you are stopping, so you arent taking a step backwards.
You were taking finasteride previously wheren't you, for at least 6-12 months? (because finasteride should be the first drug you try, for lots of reasons, moving on to dutasteride only if finasteride isnt working for you...)