X-Blems are not used on tour. Pro-pins and Pro cg's are, but I have never seen a X-Blem on tour.
I have drilled many for people and have heard mixed reviews. Just remeber, there is a reason the ball is a blem. Could be color which would not effect ball reaction, some are mismarked. Hope this helps.
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Me: "These lanes are tight. I have 2 boards!"
My buddy with front 8: "Me too!"
Me: "Yeah, but yours both have arrows on them, and an arrow in between!"