Hi You're doing the right thing by not playing with him when he's barking. But they're terriers - barking is part of playing! Sadly my DH isn't particularly well trained so can't offer any tips there.
Clicker training works on my yorkies but not Stu
As to your dilemma for the tournament. Will you have a crate you can put your pup in? When he gets to excited you could put him in the crate for 5 or 10 minutes as a puppy time out. Maybe drape something over the crate so he can't see what's going on.
If you do that a couple of times
as soon as he starts barking I can just about guarantee that he'll figure out "barking = boring crate so I'll stop barking". (it'll mean a few trips backwards and forwards to the crate and back but it's totally worth it!)
Hope this helps (and you got the advice in time for your tournament!)