Which speakers will fill 5,000 cubic ft coherently

Atmashpere, in your opinion which is more important - the speaker's relative impedance or the smoothness of the impedance curve? For instance, would an amp rather see a speaker that rated at 16 ohms which actually varies from 12 ohms to 45 ohms, or a smooth 8 to 12 ohm load? Or is it something that can't really be expressed this simply.

BTW, your contribution to the Forums is invaluable.

Now that I've sold the Kharmas (25 offers in first 12 hours and I was expecting a month or two wait..........first firm offer to buy disappeared into thin air - that really pisses me off, so second buyer, a real gent, gets them), the serious search is on: Zu Definitions, Custom-made Selah Line arrays adjusted for corners, room size and 13 ohm impedance, built in sub-woofer, gorgeous wood craftmanship, Audiokinesis Jazz Modules and Tyler Woodmeres currently in the frame. Only thing I dont like about the Defintions is the aesthetics - wife went green when she saw chrome and metal, but I am told they can be painted black.....
All input welcome, and appreciated.

By the way, thanks Ralph, for your input. Your 24/7 availability and objectivity certainly adds to the pleasure and privilege of owning Atma-Sphere amps & preamps.

My Definitions were 12 inches from the rear wall with no boom, no problem. However, I would still recommend the Presence for your situation. Black hardware is available and your wife can choose any color on earth. My speakers are the color of new copper tubing. Glossy and metallic, they look like old fashioned radios with their woofer lenses showing slivers of dark grill cloth. Flat paint is also available so you can match them to your sofa or your Navajo rug. Be creative.