I wonder what effect you would get suspending the chocolate (in the form of 80% cocoa chocolate bars, crushed) in mesh just above the mead. That's how I've sucessfully made some kick-butt crystal clear chocolate cordials, but using white brandy or vodka for the alcohol. not a hint of bitterness

mead may have too low a percentage of alcohol to make it work; not sure.

Good luck - sounds like an interesting set of batches planned