I personally wouldn't. I don't think it will help with the attachment issue. I also worry if it goes badly, that you have to sit on it for two days. Skipping tomorrow honestly seems like the best option. Don't go just because he has a spot. Only go if you feel there is no way you can live without this until Monday.

Bringing up the stone etc again will likely get the same type of responses out of him and the same reactions with you, so I just see it being bad all together. Your choice obviously but I think it's good idea to just wait until Monday, and email if you need to talk... or call him.