Consider an animated shield instead
Consider this:
Item AC Price
Ring of Force Shield +2 8500 GP
Large Shield,+1, Animated +3 9170 GP
The animated shield can definitely be used with a 2-handed weapon or with two-weapon fighting. It has a higher AC bonus. And I believe that it can be reasonably argued that, while animated, it doesn't cause arcane spell failure or a penalty to attacks for non-proficiency. All for a small premium in price.
Consider this:
Item AC Price
Ring of Force Shield +2 8500 GP
Large Shield,+1, Animated +3 9170 GP
The animated shield can definitely be used with a 2-handed weapon or with two-weapon fighting. It has a higher AC bonus. And I believe that it can be reasonably argued that, while animated, it doesn't cause arcane spell failure or a penalty to attacks for non-proficiency. All for a small premium in price.