Well, thankfully it didn't take 'all night' like the client scared me that it might. Once we got the foam dispersed enough to SEE, we seemed to have a clear homogeneous solution after only about 3 hours. Still, I didn't get home until about 9:30. We shall see what the sample looks like tomorrow.
And, gosh darn, these things are cute. Can anyone tell me what this one will end up like (assuming it survives)?