In a sunny window a plant will most likely experience photoperiod stress (people going into that room at night and turning on the light, etc) and likely go herm.
I don't mean to be rude but after 5 years of growing, haven't you had problems with windowsill plants? It's a method that most growers try once, when they first start, and BEFORE they have read any literature... and then never do again. You need a proper greenhouse to do an indoor sunlight grow. REally.