Ball Head Mount Tripod

[PearlWhiteGT]

I'm looking at some ball head mounts to replace the stock system on my bog pod death grip. I'm debating between a 46mm and 52mm. 42mm is rated to 44lbs and 52mm is rated to 66lbs. My heaviest rifle at the moment is a LMT 308 MWS that is around 13lbs the way it sits. So the 42mm should be more than enough correct? Any reason why I should pay more money for a larger ball head?