Court, they're all right! Could have been a bad butt (it happens), so try again! I've pulled butts at 188-190 that were fantastic, but it depends on what RG says...how does it feel? Once it gets through the stall, and is climbing steadily, 188 is possible. But, I've had many butts go into a "secondary" stall in the 180s. As for fat caps, I don't leave much of one on my butts. There is enough internal fat that they come out great - assuming good quality meat!
If you have a Sam's near you, check them out. Costco only sells boneless butts, which I personally don't like. You also want to make sure your cut is a bone-in Boston butt, not a picnic shoulder; totally different cut, that certainly would be dry at 188.
