For another occasion I recommend the brown mylar parcel tape. Epoxy doesn't stick to it and we use it extensively in boat building circles for ad hoc moulds. Rather then the original pickups I suggest using balsa wood wrapped in parcel tape, because it can easily be removed after the epoxy has set. I think in this application I would mix microfibres, sawdust or sanding dust in with the epoxy to make it easier to screw into.