First, I would do more than 3 kuhlis; at least 5 or 6, as they like to be in groups, and you'll see them more often during the day if they feel comfortable.
I've never kept tiger barbs with kuhlis, but I have kept various other barbs with kuhlis. Generally, as the barbs are more mid-level fish, and the kuhlis stay on the bottom for the most part, there isn't much interaction between the two species. When they do cross paths, I haven't seen any aggression from the barbs. They seem to ignore the kuhlis.