How fast is the stock HOR with a .28 or .32?
If you want an aluminum Spad, with no worries about fuse flex (which might contribute to some flutter problems), try 3/4" X 1/16" box aluminum, this stuff gets overlooked because it appears heavy. It's only 3.3 oz. per foot, about an ounce more per foot than C-Channel, but unlike C-channel it has no flex. None. It can be used as a direct replacement for PVC and other alum. fuses. For .25 engines on up, this is what I'm using from now on.