The layout you described is a 'Rico" layout named after the guy that came up with trying it. Tony uses it in one of the latest ball reaction videos posted here but I don't remember which one (although I commented about the layout).
As far as I know, the USBC nor PBA have any rules regarding layouts per se as long as all the weight rules are adhered to. As far as what appears to be a good spot, well that is to take advantage of the off balance weight of the core to produce the desired ball reaction.
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