Nine views and no comments, so I'll be the first to say welcome to the site!
That setup is absolutely a great way to open carry. The SERPA lock is a good way to get started, just so you can draw without any hangups or pulling the trigger prematurely.
You may open carry in Kentucky at the age of 18, notwithstanding what the LEO told you. Open carry is perfectly legal in KY, and as a matter of fact we just had a 2nd Amendment 'celebration' meeting in a church here in Louisville. Most of the 200+ attendees were open carrying, mingling with several LEO's. It was also on the local news channels if that's not enough encouragement.
Just do your research, be aware of off-limits carry and be confident. Is there anyone you can carry 'with' to help ease the jitters?