Several years ago when I had the discussion with the VM Specialist (he's in Derby) he told me that once they have boiled basically the heads are rubbish as the aluminium distorts too much and is usually beyond re-machining but I was talking to him about the 5 cylinder and I don't know if the same applies to the 4 cylinder. However I did take the measurements for him and he was extremely helpful, even though he told me that I had 5 unique door stops!
When I go to my mate's place I'll photo the dash, bulkhead and any other bits that I think will help you.
Regards,