OK, I actually reached out to Pivot and they're sending me a pair of the wedges gratis. The reason why I needed the wedges is because of this particular brand of grips I want to use called Revolution Suspension Grips. I didn't like the Pivot grips that came with the bike so I looked at alternatives but am limited to the ones that have a single clamp that goes on the inside, not at the tip of the handle bar where the cutout is on the Pivot's Phoenix handle bar with PadLoc. Currently have a have pair of Ergon GE1 and they're just not cutting it. My hands still get fatigued after just a few runs at Mountain Creek. I learned about Revolution Suspension Grips and I think what they have is just what I need so reached out to Revolution grips and asked if their grips will work with the Pivot handle bar since they do make a version that will fit on to Ibis bars. They said they don't and to make the suspension system work they need to have clamps on both sides of each grip. So with the wedge the outside clip will have something to clamp on to.
I think the fatigue I'm getting is due to all the pounding going down the trails at Mountain Creek, not so much from the positioning of the grips or anything else in the cockpit. If that were the case then I would have the same issue while trail riding and I don't.