So I'm doing the same thing your thinking of at the moment. I have a 55 and a refugium and this is my plan.
I currently have the 2 black ocellaris in my show tank with a green bulb nem. I'm waiting for them to host it, currently they are checking it out but not hosting yet, I can see the sins though that they will host soon. Once they do hey don't venture far really. It's all the way in the bottom right of my show tank, and the nem is happy with being there.
Next I am going to purchase a second nem, just waiting for my tank to adjust to its new bio load. That nem will go into the refugium with my 2 plain ocellaris. Once they host it, I will move hem into the 55 gal show tank to the far left, and pray like hell the nem likes where I stick him.
This plan obviously is not fool proof, and I am willing to except that I may have to have a pair of my clowns living in the refugium. But I think it's a good plan, and think it very possibly will work.