It takes three pounds to tip a properly weighted teeter. You should be OK, but you will want to train you pup to run to the very end. The further down (or rather up) the tteeter your dog goes, the more quickly the teeter will fall.

It's fun to watch tiny dogs do the teeter because they run to the end and just stand there. Then, slowly, the teeter begins to make it slow decent to the ground. Very cute!