Belgian Dubbel

We're thinking of doing a belgian dubbel sometime in the next couple of months. We already have three beers to do before then, but I was wondering if anyone had any ideas of how to do this type of beer.
We want to use belgian candi sugar, but after reading the "couple of things about belgian beers" thread I'm more confused than ever.
Isn't getting belgian style yeasts the most important part? I plan on culturing yeast from some comercially available belgian beers. To make it a "dubbel", don't you need to pitch yeast twice, and when you do that, is that when you add your candi sugar?

In the Dubbel recipes that I have, the Candi is added in the beginning to the last 30 minutes of the boil. The only other time I've used the Candi is for the primer. As for the second yeast addition, prime the beer in the second stage with another dose of the same strain of fresh yeast 3 days before bottling. Bottle when fermentation is complete, target gravity is reached and beer has cleared. As for the type of yeast, depending on the expected ABV, you can use an Abbey, Trappist, or Belgian high gravity yeast. Or just culture one from a favorite bottle of Dubbel, its up to you.

Good luck,
Wild