I've been at 54 Below many times and while I've never paid for premium seating (booth or premium section on the tables) I don't really see the advantage, especially since they are quite a bit more expensive.
The view from the bar rail seating is actually excellent (they are the same price as main dining room) and if you're worried about it being awkward, this might be the best option. It's what I opted for the one time I went by myself.
However, I've seen people by themselves many times, any everybody is lovely. It might be a little awkward if you end up on one of those 4-person tables in the main dining room vs. the long tables in the center (only the front half is premium) because there you're setting is rows of people and you'll likely have another single person sitting across from you. But 54 Below doesn't let you choose which.
I think the booth has the biggest risk of being awkward because that's often times where family and friends of the performer are seating, and they are almost always bigger group, while in the main dining you're more likely to be seating with small groups or other singles (at a 4-person table e.g. with a couple or 2 people together, and another single person).
Come early, have dinner before the show starts (I find it awkward to eat during the concert), and chat with the people seated around you, you might make friends! Or end up sitting next to someone famous (happened to my friend and me at the Marin Mazzie show haha)