Bracket opening for the beam is for 3.5....which isnt a multiple of dimensional lumber.  A pair of 2x6s laminated together is 3 wide, why on Gods green earth would you have 3.5 which you cant buy at a lumber store.  You have designed this for a 4x6 beam which is actually 3.5x5.5 and isnt available in lumber stores in our area , maybe in other areas but this could have easily been avoided.  This went from a 5 star experience to a 1 star half way through the project.  Designing for dimensional lumber would have made a lot more sense.  Buyer definitely beware.