Interesting speakers.
Dual 8’s are the equivilant of an (approximate) single 11" woofer. That’s a fair amount of "meat" and should produce a reasonable amount of bass at moderate levels without getting too "weird" in the midrange. Having dual motors and smaller cones (dual 8" vs 11") gives you advantages in control and resolution. I think this is a valid design that should yield very good sonic results. (Some reviewers agree). I’d make sure your vertical listening position height (ears) are dead on with the tweeter location. Otherwise, the "point source" benefit of the speaker will be compromised
To high pass, or not to high pass, may be a product of experimentation. There’s credible sub manufacturers out there that INSIST that you run the mains full range. I’ve experimented with this a bit, and can’t disagree with their recommendations. I think it’s speaker dependent, and volume dependent. And, yes, room dependent.
Before you start throwing money at fancy crossover schemes, you might want to just toss a quality sub (or, two, or three...) in the room and see/hear what happens. You may also find that the additional sound pressure created in the room by the powered sub(s) negates, to some degree, the need to put the pedal to the metal on the volume control, which will reduce some stress on the mains, thus cleaning up everything.
Nice speakers by the way. Well done.
