mmmmBrains
Super Freak
I re-watched Hallowe'en the other night on AMC and the guy who played him was pretty flippin' skinny. I think both the bodies you mentioned will be too big. I think he got bigger as the series went on but the H1 MM was a twig. You need one of those new slim bodies if you want to recreate the H1 look.
You're right, Nick Castle was pretty lanky at that time. Good call. I however want my Myers figure to be a bit more intimidating. I HIGHLY doubt these are tailored to a slim and I honestly don't want a toothpick Myers in my collection. Next to my other slashers he would look out of place I fear.