Over at the Traditional Bowhunter forum, Dr Ashbey has tons f articles on high FOC arrows, and the single bevel heads. His determination was that a 25deg bevel was the best compromise of penetration, holding an edge and ease of resharpening.
Are you thinking of mounting these in a slot in the end of the arrow, as a flint head would?
I have made heads with steel screw in ferrules, and the blade thickness is .060" and about 2.5" long. These weigh 300gr. That is a little less than your bands would produce.
Sheet metal of about 20ga is right about .040" thick, and that is about as thin as I would go, unless you find a high carbon (1% or more) steel, and you can temper it, otherwise it will bend to easy on impact with anything even slightly hard.