You can determine in which hand your character holds his weapon, by giving the weapon to the right weapon setup slot. The upper slot is for your primary hand and the lower for the secondary i guess. In my case the upper slot binds to right hand, the lower to left hand.
Nope, only work for dual weilding, can't equip shield in the right hand.
Yeah I made a left handed Halfling and the main hand is still set as right, but I always equip to the left anyway.
I wish it worked as it should work, but there doesn't seem to be any penalties for doing the offhand equip like I do