This is a modified version of my deluxe scale head for RTS Cyclonus. It's been scaled up to fit voyager scale figures and has both horns instead of having one cut off.
This head has a removable piece for the eyes to enable dying for light-piping or to make painting the eyes easier. The eye piece just presses in from the back after painting/dying. Be sure to test the fit before painting and remove a little material with a fine grit sandpaper if necessary to ensure a good fit after paint is applied.
There is a socket in the bottom of the head for a 4mm ball joint and an adapter peg included with the mating ball. The peg can be trimmed to whatever length is required. This configuration should provide a fairly easy attachment to whatever base figure is being used. But, if you need some modification for your custom, just send me a PM through Shapeways and I'll modify it to suit your needs.