Hi Ken!
Based on my experiences/friends with various designed presses, bronze wear plates are very much a double edge sword. They certainly do save wear on the steel portions of a press, BUT... IMO, the down sides overshadow their usefulness.
The two biggest down sides are that bronze wear plates in a press application MUST be kept lubed/greased.... and grease is a SERIOUS fire hazard in a forging press application.
I know of two individuals who had major fires in their shops because the wear plates simply got too hot, and ignited the grease/lube, and in one of those cases, the shop was a total loss.
The other down side is... with the intense stress/forces involved in a forging press application, they wear out rather quickly, much more so than in most any other application(s) and require replacement, which as you said, is pretty spendy.
I do have some bronze SHIMS that I use in Orange Crush, but they are there to take up some slack in the table's travel, and to help prevent "wracking" the press when I do something stupid.
Overall, I personally don't like, nor recommend bronze wear plates in any application that has to do with a forging press. If they're already in a press one buys, then it is what it is. If building a press, I'd suggest doing without them, and when using grease, use a synthetic that is a "high temp" variety, with low flammability.
Just my thoughts/experiences.
