What is the lowest Freq., the Eminence can put out, say at -3dB?
In my room they were hitting -3db's in the mid to high 20's.
Is there any adv. you can find by mounting woofer in V-shape instead of H or U frame other that having a narrower baffle?
Well, a more narrow baffle and less surface reflections is a pretty good reason. It worked really well.
The only problem I see in using the folded design in other applications is the limited ability to brace it well. With the added side panels and the No Rez material on the inside, it was really solid. Without those two things then each panel area is a little large for my comfort to not be able to get a brace in there.
Is there a design rationale that dictates the woofers fire front-to-back rather than side-to-side?
You can't do an open baffle with the woofers firing side to side or the null (front wave and back wave cancellation) will be on the listening axis.
A side firing woofer section would allow for a solid front and rear baffle (basically, your H-frame rotated 90 degrees) and provide a nice rear surface to mount the amp. Perhaps there is a reason not to do this (particularly with the servo-subs). Just a thought.
Sorry, it won't work that way. All open baffle designs have to face the listener.