I would go 2 more, but add them one at a time to make sure your tank can handle the Bio-load, than add from there.
You can pick up a feeder stick from most LFS to help with feeding your lion. Just place the food on the feeder stick and wiggle it, the lion should go for it. Just feed until you see a slight bulge in the stomach, A volitan should only be fed every 2-3 days, not daily.
I feed a variety of foods, for example: Raw Shrimp, Crab, Mahi, Mahi, Shark Steaks, Cray Fish, Ocean Perch, Squid, Octo, Flounder, Red Snapper, Frozen Silversides, Frozen Sand Eels & Scallops, I soak all of my foods in vitamins (Zoe / Selcon)
I do not have a UV on my tank.
Kaye