Ocellaris will adopt a saddle carpet like the one you have. It takes a while some times but they will. Unless, they are captive bred that is. With those, you may have to coax them a little bit.
Here are some points to consider with carpets:
1) Carpets get hugemungous... Mine has at least a 20" diameter when fully expanded (it stands 12" tall when fully expanded as well). They also grow that size rapidly. Mine was around 8" when I got it back around 1990. It grew to around 16" in a couple years.
2) As far as feeding goes, if you have proper lighting, they will go weeks (maybe months) without any specific food directed at them. I'm sure they are getting food from the various small crustaceans buzzing around at night and from what the clowns bring it but don't go crazy feeding them.
3) Make sure that they can find a hole to hide their column in. They like a sand base but no aquarium will ever have a deep enough bed for a large carpet. Build a tube out of live rock for their column. If you do that, they won't move on you. Mine has never moved (other than when I had to move it from Austin to Houston and Houston to The Woodlands).
4) Be careful working near them, if the tender side of your forearm gets stuck on them, it can cause quite a painful rash. Also, they are so sticky that it is difficult to get loose without damaging them (especially if you panic).
My goal is to pass my carpet on to my kids when I no longer can take care of it. They are believed to have an indefinite lifespan so if we don't manage to kill them off, outliving us is a definite possibility!
Good luck. I saw that carpet at AC on Friday and thought it looked very healthy. It should do well if you provide for it.