it won't matter. About a year ago, I had a lionfish that I kept fat and happy, but he still ate smaller fish whenever the opportunity presented itself, even with a stomach bulging with krill and silversides. I had to feed my angels 4-5 times a day to keep them from eating my LPS corals for a year and even then they nipped at them from time to time and ate my Xenia. We can try to curb what nature intends to do, but at the end of the day, if that clown comes too close and the puffer gets a hankerin', kiss nemo good-bye. Sorry for being a downer, I want it to work for you, but fish are just fish. I have seen my shark throw up food to eat more food when he was clearly stuffed. Predatory fish just have that instinct.
If you want to try to curb it, feed him 3 times a day, little bits at a time and in a corner away from where your clown lives. Hopefully he will associate the location where you put food as the only place he can eat. My angels did that and would tell me when they were hungry by schooling in the corner where I put food. Best of luck to you
-Doc