Strictly from a food safety perspective, 7 hours at 100°C will very probably get you to where you want to be.
HOWEVER... if that is your target, you will be left with a tough hunk of meat with lots of fat and connective tissue, and I'm almost certain you will not be happy with the result. To achieve tenderness, you need to go pretty far past the safety recommendation.
For slicing, you'll most likely need to hit around 77°C (170°F) internal, give or take a couple of degrees. For pulling, your internal will probably have to get upwards of 90.5°C internal (195°F), or even higher -- again give or take a couple of degrees.
To get there, I don't know if 100°C is going to cut it, especially in 7 hours. I did some pulled pork yesterday out of a Boston butt (part of a whole shoulder), and it cooked 8-9 hours at 122°C (250°F).
If I were to offer some advice, I'd say crank up your cooking temperature by about 25-30%. Also, use the thermometer as a general guideline for when to start checking for doneness, not as an absolute measure. Once you come within a few degrees of your target, use your eyes as well as the feel of the meat to determine whether you're ready or not.
Check out some barbecue forums for better, more detailed advice. Even if you're roasting your meat in the oven, the same concepts still apply (sans the smoking aspect). I recommend: