I went with the Oto's. It seems there is a shortage on YoYo's in my area at present. There are 3 fish stores around here and they were all out with no idea when they were getting more :( I was able to trade in my red tailed shark though. They wouldn't atke the balla as he was too big. So I picked up 2 more oto's making 3 in my tank, and added 3 more tiger barbs, for a total of 6.
So I need to find a place for my bala, and then I will add 3 or 4 more tiger barbs, and 2 more oto's once the current fish are settled in and make sure everything is ok. (and wait for some yoyo's to come in)