About to pull the trigger on this combo. Thoughts?

I would get the 12,000/1,200 hitch. Better to have a little more than necessary, than be equal to or short of your needs. You may also want to consider the Andersen WDH. Theirs are all 14,000/1,500 (2 5/16" ball), so you know you will be in great shape. Theirs also use a very innovative design that is exceptionally quiet and includes weight distributing, anti-sway and anti-bounce features.