Material:
Aluminum (6061 etc.) to save weight, slightly more expensive than steel plate,
2024-T6 or 7075-T6 is what current aluminum rockers are made of, or should I say, better quality aluminum rockers are made of(Jesel, T&D, etc...)6061 is really one of the the lowest strength grade alloys and not good for a product like this that has the potential to have the load bearing it could be subjected too. I think 1.7 ratio would be a good one to select, and a bushed rocker with a roller tip would yield a pretty good all around product.
Some sort of steel alloy could be a second choice, but the cheaper material costs compared to the aluminum would be made up for or exceed the aluminum in the longer machining time to make.
