@knotscott I contacted B&W about the tweeters. They told me they are sealed units and not servicable. To make it worse, they don't have any replacements. So if they're inop, I'll just have to replace them.
Chances are I'll have to figure out the gain issue. I'm guessing that the ML-335 will have just a bit more oomph than either the Defy7 or ARC VS-110 I have.
@68pete With regards to the condition of the ML-335, I don't know yet. I'm planning on sending it to Pyramid Audio in Austin to get it tested and serviced before powering it up. Were I to power it up and a cap went up, it would take out one or more of the unobtanium circuit boards then I'd have a boat anchor on my hands. It too has been sitting for 30 years. Chances are it'll need a recap.
Before figuring out any potential bi-amp scheme I'm planning on doing some listening with each amp in a singleton configuration like pop had it set up. Who knows? With all this hardware at my disposal I could even tri-amp here!
Happy listening.