Not sure if you are still looking for a false anenome for your clowns but I had a similar problem recently. I wanted to get an anenome for my pair of pecula clowns but had very little experience.
Having done a lot of research I decided it was better not to opt for an anemone as my inexperience and their difficulty with care would inevitably lead to its demise. I'm not one to give in so I asked around for advice.
I settled on a 7" leather coral with long polyp extensions (apologies I know they've got a technical term but I can't find my book to help me look less like a novice
(I already have a small 3" leather coral which they used to guard but nothing more so I was a little dubious.)
At first my bicolour blenny used it until i found him a barnacle then after about a week or so the clowns starting cuddling underneath it and against it. Once the coral was settled and got full polyp extension (~3 weeks later) the clowns fell in love and have totally adopted it as their anenome.
They defend it against any potential invaders (mainly my yellow tailed damsel) and use it a a bed! Both rub themselves all over it and collapse on it as if it were a matress. I don't think they have ever been happier.
I have no idea whether my perculas are wild bred or captive as I took the tank on from someone else. So i don't know whether they have ever seen an anenome before. but the above worked for me.
I've had hours of entertainment and joy watching the pair of them in their new home.
Good luck. Hope this is helpful.