Just to add to the research here,
Platinum with Mercury vial stacked on it, Mercury, Palladium, Silver
Platinum, Mercury, Iridium, Silver
I tried this recipe, and got
1 Mummitomium
10 Iron
1 Supernovium (8,813)
No woohooium
I have ALL EPs and SPs. I did it repeatedly, same result each time.
So at least for me, it seems to be a reliable recipe for Mummitomium, but not Woohooium.