While there is no stated evidence that I am aware of, I believe the uniforms in the STO universe have completely eliminated the command color distinction. In this timeline, red represents security and tactical, not command.
True of the default color for Tacs, but as you stated, with the Tailor options, it could be purple for all the player cares.
Of course if you like the proper original TOS color schemes, it's
Engineering/Security: Red (hence the term 'Redfshirt')
In my color schemes for my characters, we switched back to the TOS standards. In fact, our command color is a darker gold. With Operations being the more standard gold. To offset my admiral and my first officer from my navigator.