Overkill yes but it sure is NOT going to hurt anything to use it. If I were you I would use it. Crazycraftsman told you correctly as far as what others are running but No sense in going out and spending MORE MONEY to buy something just to have what everyone else is has. Of course they will be others that will immediately say "you are adding unnecessary weight" these are also the same guys that weight close to 300lbs, they must not be real concerned about carrying a few extra pounds or they could lose more themselves before they start trimming it off their mowers. 2x2x1/4 weight in at 5.41 lb per liner foot and 2x1x1/8 is 2.25. If you use a 24" piece you are only talking 5 pounds +/-.
Anyway, what I am saying is use what you have. That is what this sport WAS supposed to be not trying to be like everyone else. You will be spending enough money as it is no sense in spending more when you have a piece of tube that will work.