The mace specialization perks don't work off your weapon's damage at all, they ignore a percentage of the enemy's armor (which would reduce your weapon's current damage by a percentage, so I guess they work off current damage in that sense). If the earlier poster is accurate in saying that most meaningful enemies have 0 armor, though, then the perks are completely worthless. (Really, though? Dwemer constructs have 0 armor? But that's the entire reason I took mace perks in the first place - it seemed like the most sensible way to get an effective attack against the steambots!)
As to the question in the topic, I strongly favor one-handed. I tried two-handed weapons for a bit, but they're just so slooooow. Take one swing, then go make a sandwich or something before you're ready to attack again. It also seemed very fiddly trying to switch between attacking and blocking with them. (Yes, you can block with no shield if you're only wielding one weapon.)
One-handed weapons are a good deal more responsive, plus they give lots of options - you can do the sword-and-board thing if you want to, but you can also put a spell or a second weapon in the other hand as the situation demands.