I'm afraid Slayer isn't really my thing so it's not something I've ever tried. I have, however, just devoted some time to listening to some Slayer tracks, including 'Show No Mercy' to try to make sure I'm saying the right thing. Their tone is certainly dry, hence the suggestion of an Aftermath is entirely logical and there seems to be a fair bit of compression going on there too. The Cold Sweat may be a bit too open sounding for that tone so of your top two suggestions, I'd say the Holydiver would be more likely as it's thicker and carries a bit more compression. Having said that, I still feel that based on the limited amount we know so far, the Juggernaut would be my first port of call.