Yis,
I once caught a blacktail in gouritz river... i wasnt at the rod at the time. I came back and found the rod on the ground.
I reeled in and found a semi concious blacktail on the hook. You could clearly see a kob had grabbed it.... the marks showed it grabbed it from the stomach side, i think the blacktail was a little big for the fish that took it.
If you are casting a mullet, chances are the kob will engulf the entire fish, even if it's a small kob. A small kob will easily take a whole pilchard on a 10/0 hook!!! As said above, most important is the amount of time your bait will stay alive, secondly a proud hook. For elf i would definately suggest a hook near the tail. Remember elf bites off a piece... kob swallows whole, and it would struggle to swallow a fish in reverse.