a couple suggestions for you
add sugar to your brine, it will balance out the salt, the baseline brine posted on this site under Cooking Topics, All About Brining is what I'd suggest:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">1 quart cool water
1/2 cup Diamond Crystal Kosher Salt
1/2 cup sugar
Mix in a non-reactive container until dissolved. Substitute 1/4 cup + 2 TBSP Morton Kosher Salt or 1/4 cup table salt for Diamond Crystal.
Make 1 quart of brine for each pound of meat, not to exceed 8 quarts (2 gallons). Soak meat for 1 hour per pound, but not less than 30 minutes or longer than 8 hours. If brining multiple pieces, base the brining time on the weight of an individual piece. </div></BLOCKQUOTE>
that solid mass of meat will likely need more time in brine than 2 hours, I'd guess about 8 hours for the full effect
given the half hour rest I'd remove it at 155ºF tops, probably 150ºF
You might fire up the grill, get it real hot then sear the outside before smoking. This will make the exterior a little nicer and add flavor, but will kill any chance at a smoke ring if that was important to you.
If you're interested you could try flavor brining. Orange garlic and ginger for example. It needs to be fairly strong to come across in the end. Stronger than your natural instincts tell you. For that example something like juice and zest of 1 orange, 1/4C fresh thin ginger slices, 6 smashed garlic cloves, 4 whole cloves. Boil brine, then chill below 40ºF before brining.