Thank you for the advice, gentlemen. You both are the most knowledgeable people here on Audiogon regarding Apogees, by far.
Dave, the dimensions you worked out are just about right. I have pretty much placed all of my speakers about 3.5' - 4' out into the room, with about 6' - 7' between them. Though they seem closer to the walls, one of the walls is actually an opening into another room. I have always preferred to listen in the nearfield, with the speakers toed in considerably - aiming right at me. And, yes, this is, for all intents and purposes, a dedicated listening room (in the guise of a "sitting room").
I have heard that both placement, and vertical angle were keys to getting most Apogees, these Calipers Signatures included. 48" tall is probably ideal for me. While Divas are obviously out, it sounds like the Duetta Signatures also fall into that category - unfortunate!
It sounds like volume will be no problem. One thing I have always heard from people quite in tune with Apogees is that, despite what most think, the bass is absolutely concussive. That's exactly how I like mine.
Vince, I will definitely see if Henry will have me over. If I am lucky enough to end up with this pair, his amps are already on my shortlist. Partly from following you in these threads over time. Tonya Harding and Tara Lipinski?!? I'd be more than a little happier with things if the Stages and Caliper Signatures were Surya Bonaly and Kristi Yamguchi. Dorothy Hamil sure is good enough, however.
Wish me luck!