Sounds great. I always worry about the fermentability of extracts, but there isn't a whole lot you can do about it. Looks like you had already incorporated the suggestions I had for you. I like the percentage of sugar, the choice of hops, the OG and IBU, and the yeast. So no further suggestions there; looks like you're in good shape.
Only thing it doesn't mention is the fermentation temperature. I'd start in the low-mid 60s and let it rise on its own as it goes. Don't try to rein it in, but also don't start it too hot. You want to avoid making liquid headache.
It's rather see a tripel a little small than one that's too big. Especially if you're working with extract.