I still don't think tactical is the way to go... too wannabe. I mean, like you are really going to be all SWAT team just because you had a ride-along?
You really should dress more conservatively, so I still think you should go to the local uniform store, buy the same uniform as that department, navy or tan/green or silver tan, whatever. Then put on captain's bars or 3 stars for deputy chief on the collar. Shows you are ambitious but not too overly presumptuous that you are wearing 4 stars.
Guns! More guns! I need more guns!