It was answered in another post.
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SP said...katana said...should be ok but will have more flex in the base.1/2 inch tabs are for center boxes only

Thanks, think katana was answering my fin topic, yeah they are controller quads, they seem ok with a shim under them, they actually make a shim for them so you can buy either size tab. The 1/2 inch boxes for quads were brought out later as some HPs are to thin in the tail for the 3/4 or so I was told.