For what you are using it for, imo the 2.5-8 would be a better choice. Both are very bright...and I personally would NOT get the heavy duplex. I had one, sold it after one season. I hated it, but that is me.
If you are intent on the expensive Leupolds, you might want to look at the 3-9x40 Zeiss Conquest. I think they are as good (actually a little better) than Leupold.
Honestly, for what you are saying...I'd probably get a 3-9x40 VX II. They are on sale right now for $239 at several places. You won't notice the difference between that and the III, imo. I have had both models in various sizes...that is my opinion. Even a 2-7x33 might be perfect for you. I have one of those too on my sons gun. LOL
Best thing for you to do is go somewhere and look through a bunch and see what gives you the warm fuzzy.