Re: What HB for a plywood archtop?
I would try the VPAF Bridge in the neck position. That pickup is very open sounding, and should add a little pseudo dynamics to that hard top. Actually I have the neck version, but I imagine the bridge version being a little fatter, which is what you need. Otherwise there's always the Alnico II's, they would warm it up.
What's impossible about your predicament is that you want to introduce dynamics where they don't exist. The wooden bridge is probably the best choice. For a slightly more distinct tone you could try the Bartolini PBF55/57 combo, and I suspect you'd end your search. You might have to think outside the box, since no matter how "vintage" you go with your pickups, the only thing they will do is more purely amplify your already lackluster acoustic tone. The Bartolinis would add some "Sprucy crispness" that you aren't getting from the laminated Maple, as well as more string-to-string separation, which is the kind of thing you get from a better quality solid top. So they could fool the ear better than a typical Dimarzio/Duncan PAF variant.