I use an overdraw on my target bow for aluminum arrows but it is a very modest 1". The reason I bought it was that it had a great arrow rest and it was in the Bargain Bin at the archery shop. I have heard that the the bow becomes less forgiving as the overdraw length increases. Someone else would know better than me on that one.

For every 1" of overdraw, you can cut your arrow length 1" for a weight savings of about 10 grains (aluminum). Going to carbons you could keep your length at 31" and save 50 grains or more. Going to carbons alone would allow your bow to shoot the same trajectory at 30 yards that you now shoot at 25 yards. Not bad eh?

You should probably look at carbons as a first step since you need to buy new arrows in either case (because length affects arrow spine). The carbons are much more durable as well. I use carbons on my 37# recurve and they really zip! I was shocked at the trajectory I was getting with such a light bow.

Good Luck