The Two Handed Warhammer does less damage than what you might think, there's a reason why Bar Mace/Long Iron Mace have been, and still are less popular than Morningstar, even after the -2 speed nerf to the latter.
I still loomed one to +3 because it's a fun weapon though.
Assuming you have 6 PS and 181 WPF after penalties, below is a list of armor levels, followed by the amount of cut damage needed to surpass 35b.
79 armor, 51c
70 armor, 49c
60 armor, 48c
50 armor, 46c
40 armor, 44c
30 armor, 42c
20 armor, 40c
10 armor, 38c
Against the Kuyak user, your heavy great sword would've probably done around the same damage as your 2h Poophammer Warhammer.
Against the peasant, a +3 bastard sword or better would've done more damage.
Against the highest armor you can possibly run into ingame (+3 Milanese Plate with +3 Heavy Gauntlets = 79), you'll do more damage with a +3 Celtic Axe (51c).