(Advice?) New head for Onslaught

[MechanovaKing]

I'm aiming to chopper of Heat-Wave-Moive-Onslaught's head and replace it with a head that looks more like G1 Onslaught...something like...i don't know...G1 Onslaught's head?

[Thats the best I could do if anyone has a better idea for a new head I'm all ears.]

But in the mean time; G1 Onslaught got a huge hole in his head. What would the best way to fill that in and model a new back-of-the-head?

Heat-Wave-Moive-Onslaught has a rivet in the bottom of his neck rather than a nice screw. Is there an easy way to remove that and plug that into the new head?
(He does have a screw on the back of his head but all it does is removes the light piping)

{I know I've seen custom FP Combaticons somewhere on the net once before. I'd also like if someone has a link that would maybe get me in contact with someone who's already gone down this path}

[Shepp]

Hmm......... Would it be too disproportional to use Headrobots Butcher as the new head?

[Hobbyist Prime]

That huge hole in his head is to attach his base mode to Trypticon but if you need to fill it I would suggest a modelling putty from a hobby shop.

[brr-icy]

green stuff, epoxy sculpt, should fill it, butcher would be huge, an ultra head on a deluxe. there's a couple people who cast the heads too

[MechanovaKing]

green stuff, epoxy sculpt, should fill it, butcher would be huge, an ultra head on a deluxe. there's a couple people who cast the heads too

There are? Can you direct me to them?