Well, it didn't quite work out that way. At first, the two dogs were ok--not playing, but investigating--but Vanya, as always, came on too strong, and when Andre told him to buzz off a bit, Vanya failed to do so. They danced around for a while, and then Andre had enough of Vanya and nipped at him, and we ended the session because Andre was clearly feeling overwhelmed by Vanya.
When I pulled Vanya away from Andre, at that point, he started shrieking and trying to pull out of his harness, and I had to drag him out of sight. He took quite a while to calm down, even though he was crated in the car. When we then walked over to the picnic area where Lana and Andre were waiting and tried LAT from a distance, he was still far too wound up to do it. So then he went back to the crate in the car for another cool down, and then he was able to stay calm (more or less) and do LAT with Andre in the distance. We could actually get quite close without Vanya reacting, just so we went back to the visual barrier of the car for brief cool-downs. Targeting a lid was also quite helpful.
I also put Vanya in his crate, outside the car, and fed him peanut butter and played LAT while Lana and Andre walked around the parking lot. Vanya did much better at this than I expected, until Lana and Andre approached us directly, then he started vocalizing (not aggressive barking, but his shrieking "let me, let me, let me have what I want!")
So: what did I learn from this?
1. leash control: I had dropped Vanya's leash, so that he wouldn't start screaming at leash-restraint, but this was a mistake. It would be better for me to hold onto a leash and do my best keep it as loose as possible, while the other handler uses a long line, and allows her dog to leave Vanya if he gets annoying.
So, in essence, I should be doing Donaldson's "On Leash Meet and Greets With Tarzan" (pp 50-53), rather than "Remedial Socialization" (pg 34), unless I can find a group of 3 to 4 solid, calm, large dogs who like rough play.
2. Choice of dog: I had thought Andre fit Jean Donaldson's "bomb proof dog" definition (pg 29), but he's too young and inexperienced, and too vulnerable at his age to fallout from a bad experience. (He is huge, but only 10 months--which alas, I didn't realize until afterwards, because I would not have let him interact with Vanya if I had known). Plus, of course, he's male, and Vanya's likely to do a lot better with a female. So I'll need to find a calm, playful, bombproof, female lab. Any ideas?
3. Muzzle: Vanya finds his basket muzzles too heavy on his nose. He's been conditioned with a ton of cheez whiz, so he doesn't fight them, but his ears go back and his expression gets spectacularly sad. More importantly, I think the basket muzzle may make him more reactive. I've also conditioned him to an ordinary, padded vet muzzle that is quite wide on him, so he can easily eat and drink with it. He seems completely oblivious to this muzzle--it doesn't appear to bother him at all. I tried Amber's basket muzzle, but it also seemed to put uncomfortable pressure on his nose. Interacting today with the vet muzzle on (for only a few minutes), he didn't seem to get at all heat-stressed in it, or reactive from it. (The temperature was 50 degrees and drizzling. Most importantly, I worried a bit that, because the vet muzzle was so wide and loose on him, he might be able to nip with it on. But he couldn't, and he couldn't get it off (he didn't try). So for short socialization sessions in cool weather, the padded muzzle will work.
5. Next time: we'll start at a good distance, keep both Amber and Vanya well under threshold, use the cars as visual barriers, and do BAT and LAT. Then, if the dogs manage to stay calm, we might try some of the calming routine from Liz's class with Ginger.