What level of optimization should I choose for release?

Question

I read about quick statements here and trying to learn more about optimization.

for debug (default):

Compiler

It doesn’t perform optimizations, which, in turn, debugs your code and tracking it back to the source line of the source code is much easier.

for -O :

the compiler will strip characters from your code (e.g. variables and function names) and optimize the code to improve its performance

for -Ounchecked :

This is the level of optimization you want if you are planning the absolute best amazing performance. Although this level of optimization improves productivity, it achieves the introduction of a certain level of risk. With this level optimization, the Swift compiler will skip many of the security checks that it usually runs in code to squeeze the last ounce of performance

My questions:

• To speed up the work of users ... when archiving and releasing an application, do I need to change anything? Or do archives default to -O ?

• What version should I provide my users? -O or -Ounchecked ?