Well, it will be a brown ale (~21.5 SRM) with a higher kick (at 7.3% via BeerSmith, factoring efficiency for your estimated/target OG). It's a bit above the American brown ale style range in IBU's. Consider moving the 15 minute addition to 10 minutes. You could also move the 5 minute addition to either 1 minute, or at flame-out.
I would plan to ferment in the lower 60's if at all possible for you. See how it tastes after 3 weeks. It's highly likely you'll want to give it more time so that it's not as hot.
IME, brown ales are really good when balanced (IBU:GU) and given enough time when bigger (above 6%).
If you want to get it darker, without using more dark malts (3.4% chocolate is getting up there), consider doing a caramelizing boil with part of the wort you collect. Pulling off even a gallon, and reducing it down to a quart (pint, or less) will get it to darken. It can also bring something extra/special to the brew. At least look into it and decide.
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