My friend if your bending up arrows that much, you got something else going on. Like missing your target way too much. Have you ever put a set of carbons on a spine tester?

LOL My friend, I don't ever miss my target. I use 1" sticker dots and shoot 1 arrow at 1 dot, never shoot 2 arrows at the same spot, that wrecks even carbon arrows. I started with aluminum. Didn't always have the best targets, I've bent more than a few arrows just pulling them out of my targets.My 1st dozen aluminums lasted about 1 month before they were all bent up. I switched to cabons before my first year hunting. I have 1 carbon arrow that's about 5 years old and has killed at least 6 deer, will be arrow #1 this year. I've never lost a carbon practising and have lost more carbons hunting than I've broken. 7 Years of bow hunting I average 4 deer per year.
I use Easton Axis arrows and have abused them in many ways and they keep right on working, have been much cheaper in the long run.
The author of this string I believe is looking to reduce his draw weight so he can keep shooting? Aluminum may have more KE right off he bow, but will not have more KE down range with a 30-40 lbs draw weight. IMHO a small diameter carbon with the correct spine will give him better performance down range. With lower draw weight, getting the correct arrow matched up to the bow and shooter is more important than ever. I wouldn't use any 4" vanes.
One product I tested that might be of interest here is the FOB. Replaces vanes but you need a good drop away rest. With the right arrow, the FOB's will get every ounce of down range energy out of that arrow. See my post in archery equiptment reviews. Otherwise I'd sugest 2.25" Quik Spin vanes or 2" Blazer or 2" QS Speed Hunters. (my tests rank them in that order after FOB's)