Well, I guess the best thing would be to pray as often as possible.
Also, if there were maybe 3 specific times a day that people could stop, offer a prayer, then do a healing visualization, that might offer a strength in numbers.
I'm suggesting 3 different times so that people with their different schedules will be able to hit at least one of the times. (2 times would be even better, etc.)
How about: 11am, 5 pm, 11pm Eastern
Of course if you're on the west coast:
8 am, 2pm, 8 pm
Central & Mountain, or if you're in Europe, figure it out.
Since it seems there's a greater power in numbers, spread the word to other DS message boards you belong to.
Also, I googled "healing groups" and found one called The Osel Group where between 400 and 800 Buddhist monks will pray for you. (!) So I requested healing prayer for Craig. If a bunch of people could submit his name to other healing groups, that would really increase the number of prayers. I had better luck with "healing groups" than I did with "prayer groups". There seem to be tons of them but there's a lot of prayer stuff that has nothing to do with healing.
So, does this sound reasonable? I don't know much about this type of thing and less about organizing it.