Now I'm guessing that you are new to this and you want something from all us out here????First off you started out good with Jeff's rub and all but you lasing with the 4 hours part. Baby backs need that last hour for good tenderness. But......We really need alot more info.
For BB on a MES I do a 2-1-1 method at 225. After the last hour, I cut them into manageable pieces, dunk them in sauce (I prefer that to brushing on the sauce) and sear them on the grill to carmelize the sauce.