My pair of percs live and spawn in a GBTA.
Percs and ocellaris are just about the most difficult clowns to get to live in an anemone that they don't live with in nature. 99% of the "how can I get my clown to go into its anemone" questions are asking about percs or ocellaris. Some go right in, some take more time. I had an ocellaris pair that went for over a year before they accepted their GBTA.
FWIW: IME, the bigger the BTA, the better chance you have of your percs accepting it.