Thank you all for the complements, I appreciate them.
snapsc, regarding your ultimate question; for a person who values the bulbous soundstage and sense of grandeur above all, I believe the F5 would be very gratifying. Because it has a built in subwoofer, it can be downright impressive in presence and scale, two aspects that can yield a sense of an overwhelming experience. It's unusual capability to be contoured to nearly any set of electronics should satisfy all but perhaps the most hard core ESL or horn lovers. It is a legit dual purpose speaker for stereo and surround systems, should a person wish to use it for that, too.
I was surprised by how handily the F5 outperformed the Walsh Model F - and that was with the vintage speaker being modified by removing half the dense dampening material and bypassing the fuse! The difference in capacity to perform at a very high level was strikingly in favor of the F5. Though it was not my intent to demonstrate it, as I had no idea how the comparison would turn out, the result once again supported my conclusion I reached years ago that vintage does not typically have the capability to perform on the level of contemporary designs. Looking into these older designs literally, there was nowhere near the fanatical attention given to cabinets, dampening, bracing, etc. that happens now, and the character of the performance is fundamentally different. Imo, modern cabinet making for speakers is on a higher level and my ears enjoy the difference. Imo, the appeal of vintage aesthetics is not enough to overcome the performance gap. YMMV