How long to wait before installing UEL catless headers on rebuilt FA20?

I recently rebuilt the FA20 in my 2013 scion FRS and I’m trying to do everything right during break in.

I’m planning to run UEL catless headers, but I’m unsure:

How many miles should I wait before installing them?

Is it safe to run headers during break in as long as I’m on a proper pump gas tune?

Should I heat wrap the headers or leave them bare (concerned about moisture/long term reliability)?

At what mileage is it generally safe to start pushing the engine harder (higher RPM, WOT pulls)?

For context, the engine was rebuilt recently and is currently in the early break-in phase(100-200 miles). I’m not planning to go E85 or aggressive tuning until later just trying to avoid hurting ring seating or causing long term issues.

I really want to put them on but idk if they would cause any damage.

Would love to hear from anyone who’s been through a rebuild on these cars or has tuning experience with fresh FA20s.