Yes, the 1/4" spacers are required to clear the upper A-arm. Generally they are needed for any tire wider than a 285 but it depends on the way the truck was built and when it comes the 35x12.5's, what the actually measurements of the tires are. Some actually measure 12" while some measure up to 13.5".
Glad your set up worked out though. As Cowboy said, a few pictures would be good