APA little bastard brake and tbac Ultra 7

I'm confused. I'm having a rifle built and have an APA brake. I also have a tbac Ultra 7 that I want to be able to go back and forth with. My tbac is in nfa jail but I was told comes with a compact brake. If I want to direct thread the can on my barrel, do I need to have my gunsmith thread my barrel to 5/8x24? I want to be able to take off the APA brake and thread my tbac on when I want. What do I need and what do I need to tell my smith?

Discuss with your riflesmith.
Bad idea IMO to do frequent swaps with muzzle devices.
Easy to stretch fine threads beyond their designed limits distorting them, affecting timing and strength.

I would recommend using a QD mount if you plan to do frequent "swaps". JMO YMMV

If both brakes are 5/8x24 yes that's what you want your barrel threaded.

How often are you going to shoot suppressed? If most of the time, skip the APA and just live with the Compact Brake when you shoot without the Ultra7.

If you are going to shoot without the Ultra7 most of the time, you'll just have to screw the CB on before using the Ultra7. No different from a direct thread suppressor.