I also have 2 Yorkies.
I had my first one, Hendrix for four years before I brought home Lucy. Let me tell you, that first week was HELL!!! I called me mom and my vet in tears thinking that I had done the worst thing ever. Hendrix was going to the bathroom and vomiting EVERYWHERE. THey were fighting. Hendrix would not even look at me---- it was AWFUL.
However, I got through that first week or so and my two babies are now BEST FRIENDS!!!
Hendrix still get annoyed with Lucy every now and then because she is a baby and she annoys him, but they really really love each other.
Also, it is so much easier having two dogs rather than one. I do not feel so guilty now when I have to leave the house. They keep each other company, they play together..... they have so much fun!
If I were you I would DEFINITELY give them at least a week together. I havn't read what other people wrote, but from my experience you really just need to give them some time to fight out who the 'alpha' is and come around to each other. Of course if there is yelping or they seem to be hurting each other then you should step in and pull them apart.... but I usually let mine fight it out when they are fighting over something.... they are dogs- that is what they do. They need to show one another who is in charge. Animal instincts.
I do not think it matters that they are both boys..... there may be a little more drama as they figure out their place in the family, but when it comes down to it, they are both still young enough that they are not set in there ways........
I am sure that everything will work out- JUST GIVE IT TIME!
Love,
Sarah, Hendrix, and Lucy