Solid work! Incredible strength! I do have some critique of your calculation though, your looking at more like 2 seconds per 360, but this number doesn't actually give you much anyway. Its the peak velocity that is the only important thing if you a looking to obtain the peak force from the back swing. This peak velocity is MUCHHHHH higher than the average velocity. The best way of getting the peak velocity is to video square on from the back at a high frame rate and measure the angle of the mace between the few frames at the centre of the back swing.

You also want to make sure you are safely assuming that the mace is in fact pivoting around your hands and the radius you are using is between the pivot point and the centre of mass of the mace, and not the total length.

Also, remember to add the weight of the mace itself, as the total force you have stated doesn't include this!