Can’t deal with Hetfield’s vocals on KEA, so the obvious choice was out. Not really a Deep Purple guy, and RIP has a few weaker songs on it. Pantera and Slayer are non-starters for me.
That left SFV + STTG vs. O:M + DF. Since Operation: Mindcrime is almost flawless and Dr. Feelgood at least sounds pretty good, I had to go with that pair.