Opalchip,
Thanks for the feedback. I've found that the listening position needs to be as far from the line between the speakers as the distance between the speakers. As for toe-in, I came to the same conclusion as you did - straight at the ears. Right now, the tweeters are about 3" below ear level, and I think I need to raise them to ear level, but definitely not above as they were when I started.
The TC-60s are growing on me. Although they don't project into the room, and vocals are still a little laid-back, the soundstage is quite precise, wide, and amazingly deep. I'm finding, too, that vocal presence is much more a function of the recording than I'd realized. Some of the tracks on Norah Jones' debut CD have her voice a bit muffled - perhaps she was eating the mic - whereas others are definitely more open. On my Mission 772s, everything sounds open and forward. I think the Spicas are revealing a lot more than the Missions about recording quality. On material with great soundstage depth, like Dire Straits' "Brothers in Arms" I feel like I can see mountains off in the distance. "Lyle Lovett and his Large Band", too, shows great front-to-back depth. Dynamics are not great, and this is where a more modern speaker will probably put the Spicas to shame. Even the Missions are better, delivering lively punch from Lyle Lovetts horn section.
My Stax Lambda Pros, like my Missions, have a much more up-close sound, which makes me suspect that the distant-but-deep soundstage of the Spicas is a bit inaccurate, perhaps a function of the old drivers' lack of fast transients. My personal preference is for a somewhat closer, faster, more ethereal sound. Still, the Spicas are very charming and involving in their own way, providing pleasures not afforded by the Missions. I expect I'll keep them until I can afford something significantly better - a used pair of Martin Logan Aeriuses, perhaps.
In the meantime, I'll take some baby steps on the electronics side. I've never owned better than H/K, and have long been attracted by the reported price/performance value of Adcom, so I'm going to try that for a while. For $110, I couldn't say no to an Adcom GFP-555, and I plan to mate this with a pair of GFA-535s if I can snag them for about $100 each, just to see for myself what biamping might do. Will repair my Mission 700as sub, and add a second if I can find one for $150 just for the hell of it. I'm thinking two subs crossed over around 100-120Hz might drain some of the mud out of the Spicas' bottom end. Might also consider replacing the TC-60s with TC-50s in that case. I know, I could probably do better by plunking down the cash all at once on something better. But, this way I can invest at a leisurely pace and learn a lot in the process.