haven't trained for or tried a one armer for ages. Tried one randomly at Rubicon the other day and managed both arms. All you need to do is strength work and hard bouldering and it'll take care of itself. Of course, if you are enjoying the process then carry on, not sure where these party tricks are performed though, never been to a party like that.
And the exercise abarro81 suggests is really good and more climbing specific, I do them reaching as far to the side and as far up as possible, also laps of 10 reps, pausing locked off at the shoulder for a few seconds. Good to do after bouldering when fingers are gone but there's still juice in the shoulders.
