How old is the first one? When I was looking for someone for Alphy I looked at one that was really hyper, Alphy hated him and I ended up turning him away.
Then I got Murphy as a puppy, he's now 6 months and full of piss and vinegar but I chalk that up to puppiness. Alphy is 3 and totally layed back and mellow. Big ol couch potato. I'm hoping Murphy will mellow some as he gets older and learns from Alphy. There are days he drives Alphy nuts but he just goes somewhere that Murph can't get to him. They currently the same size and I think that was important for me.
Good luck, guess what I was trying to say was the right one will come along and when he/she does, you will know.