Thinking 500k might be ok actually, they're currently in an alder/mahogany LP which sounds a bit duller acoustically than the SG, so I'm thinking in the SG, the tone will be similar but a little brighter. Jonathan I will give you a call tomorrow to order the parts I need :)
Just done a mock-up of the black covers in the SG as well, looks awesome! Need silver polepieces though.