What kind of hardware did you use? Not a fan of running self tappers in.
I used the OEM polaris screws and cup washers, the same ones they use to attach the skid plate, they are a fine thread tapping screw. Much better than the coarse thread self tapping screws. And I also used the oem cup washers. The fine thread screws hold better in the thin wall tubeing than the coarse. And for a little extra thread engagement drill the hole smaller than the (polaris) screw, and it will push the metal to the inside of tubeing, or you can indent it with a punch.
Other sizes will work, but I recommend the 1/2 UHMW, the 1/2 allows you to recess the washers below the surface of the skid, possibly reducing broken screws and damaged frame holes.