Adding Bronze Bushings to Ductile Iron Rockers

Thanks for the comments. If I had a set of W5 heads sitting on my desk it might be easier to just do it. I really don't understand the lack of support for w2/w5 heads or why someone isn't making new versions of those heads or ferrous rockers to match.
Because they are so deadgum expensive to build. If they weren't so costly, there'd be a greater demand.