Overhead Stereo Opinions

I’ve settled on a swamp donkey speaker box but not exactly sure what speaker setup I want to go with. I’m ordering the empty box and will be using a Pioneer headunit and Polk speakers. They have a 2-6.5 and 4-5.25 box available for the same price.

Since I won’t be using and amp and powering the speakers from the headunit, which would sound better and have more bass? It’s obviously not going to compare to a sub, but not sure which would be better. With the 2-6.5s, I’m only using two of the four channels on the radio. If I go this route, it’d be easy to add a couple more speakers in the future since I’d already have two unused channels available. An individual 5.25 would have less bass, but having twice and may with double the power might be better?

Thoughts?