Mina,
It's all very confusing. Cheesemaking.com suggests basically a 3% brine with 1/16 tsp. B. linens per cup. Caldwell suggests a much lower salt percentage, but doesn't say how much B. linens to use.
It probably doesn't matter, much. Commercial cheesemakers use it (in spray form) at much lower concentrations than home cheesemakers. Keep in mind that, under good conditions, bacteria reproduce every 20 minutes. So although there's probably an ideal initial concentration, environmental conditions are probably far more important.
Don' t let the rind dry out!
Just my 2 cents,
-L