OK No one responded so I will post what I did and how it worked out.
I found one web reference for dosage, which was dealing with Puffers. This person indicated the treatment should be done each day. Still hesitant, I decided to space it out a bit more than that. I did the 1/2 capful but added around 12 hours extra between dosages. So I would dose 1/2 cap in the morning, and add 1/2 cap the following day in the evening. I did this for the 5 days (except it ended up being 6 days).
I changed out 25-30% of the water at the end of the 3rd day just to be safe. I probably could have left the tank alone, one betta in a 10 gallon. I did see some stress in the fish each time a dose was added but within 4-5 hours that stress seemed to be gone.
The fungus is gone it seems but I am running a course of maracyn one and two just to be sure there isnt another problem lurking.
I think the problem developed when I transfered this fish from her unheated tank (its the kids fish) into the heated 55 gallon. The problem was probably lurking due to the cold, small tank and the heated water probably caused the explosion of the fungus.