I don't know about Belgium triples, but I can tell you lots about Germany Hefeweizens and England bitters. I brew an America IPA every now and again, too.
Sorry, I couldn't resist. No offense meant.
Anyway, a couple week in the primary ought to be enough. Standard wisdom around here tells that you have a good plan with the 2-4 week in each before bottling, though the secondary may not even be necessary. Given the recent interest around here in improving English ales by altering the fermentation schedule (basically, shorter fermentation times and earlier crash coolings to prevent the yeast from cleaning up so much) to give a better malt and ester profile, I wonder if some Belgian ales wouldn't benefit from this kind of treatment as well. If you're wanting to stay on the safe side, just do as you were planning, and your beer will turn out fine. If you're feeling adventurous, think about crash cooling and transferring to a secondary for a bit as soon as you are nearing FG. Let us know how things go in any case.