Snare side heads are their own animal, sized separately from batter heads. They need to be super thin to allow for snare response. Here are some general thicknesses, although it might vary a bit for specific model heads:
Batter heads:
Diplomat = single ply, 7.5 mil (mil = thousandths of an inch)
Ambassador = single ply, 10 mil
Emperor = two ply
Snare side heads:
Diplomat = single ply, 2 mil
Ambassador = single ply, 3 mil
Emperor = single ply, 4 or 5 mil
If you put a batter head on the bottom of your snare, the head's thickness will completely choke your snare response.
...and since you specified a "Super Gene Krupa", I'll mention that standard present-day Remo heads fit really snug on my late 50s Radio King. I've got some Aquarian American Vintage heads on order since they're sized for slightly larger older drums to keep the heads from binding against the shell.