Good idea to give Leo a break. I went through a similar situation a few months ago with my little Kole tang. It was easy to catch him and put him in my acclimation box and keep him in there for a bit. The "tyrants" were my O. clown and a three-stripe damsel. The entire gory saga is on my build thread. I ended up capturing the O. clown and the damsel and both went to live in timeout in my empty BioCube (well, it had water). It gave the KT time to gain some confidence in the 90 without being terrorized. Both were successfully rehomed into the 90 and everyone plays semi-nicely together now.
I have always been able to net the clown, but the damsel was another story. I was able to catch the damsel after he went after the KT and accidently found himself in the acclimation box. Oops! I was able to shut the lid before he got away....got a great cardio workout in at the same time. ;Hilarious
Another idea would be a mirror. I have taped a mirror to the side of the tank and caught a fish or two that way. I guess they can't stand the competition on the other side of the mirror.
@fishguy242 has a good idea with the red flashlight. My clown is always in the same spot at night. Might be easy to "ambush" the clown by slowly sneaking up with a net. I've used a red flashlight for years to spy on the tank at night.
I hope all ends well with the clowns and the storm!