Robbie - definitely 199-203 on the internal temp. You'll probably find the two different butts will cook differently, so I'd check them individually. I wouldn't crack the door to take temp for at least 6 hours. A remote meat thermometer is critical when doing large cuts of meat, like butts or briskets. We live and die by internal temp - it's the real key to good Q! The Maverick ET732 or 733 are great units, but a less-expensive model (like ones they sell at Academy or WalMart) are fine. I used to use an Acutemp single-probe model that was very accurate, and served its purpose. The Maverick gives me 2 probes (box and meat temp), and a remote unit (too lazy to walk out and look at the temp).
Also remember the stall! Your 2 butts will stall between 170-185 (every one is different, as far as the stall point). Don't rush it, or think it's stopped cooking. Be patient, and let it work through...the temp will eventually climb!
Good luck, and let us know how it goes!