The block ZZDoc describes will work - provided the cavity and everything are made precisely to dimensions that match it.
That may be the case on an EC Sig from upper regions of the catalog.



One of the other little glitches that accompanied my CS guitar some years ago (which most of you veterans know was built on a Clapton platform) was that the guitar came with three springs and the trem block not "stopped". The tech at the Guitar Center I do business with, and who really knows his stuff, pulled a block out of an Artist Series Clapton and cut and sanded a piece of wood to the precise specs of that block and inserted it into my guitar prior to adding the two additional springs (which were sitting in an envelope in the guitar case, )after which he set up the guitar. I cannot speak to the dimensions of that block, however, what ever the spacing is between the back of the trem rout, and the back of the steel when the bridge is flush to the top is how thick the wood block needs to be, less the sanding needed to just be able to slide it into place.

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