A sebae is one of the most demanding of light anemones that I have owned, and yes, they get GIGANTIC. I would never recommend one for the average aquarium.
Your perc clowns may/may not host in the anemone you pick, that is always the unknown.
There's nothing difficult about a bta if you have light and make sure all intakes are screened...
Once they settle they stay unless you make a dramatic change.