First post of 2019! I just noticed this morning Sprint's coverage maps are transitioning to showing C-Spire coverage in Mississippi as native 4G LTE rather than "Extended 4G LTE".
I've been trying to gradually map out Sprint's LTE coverage on CellMapper in the Jackson metro area using my Google Fi, but over the past few months when I force it onto Sprint, it often switches me over to C-Spire towers even when I'm in the Sprint footprint. I can't seem to do anything (reboot, switching network, etc) to force it back onto Sprint towers, either. It's a plus for me having better coverage, but it has made it difficult to map out Sprint coverage. I'm not sure what the experience would be for someone using regular Sprint service, but I've contemplated getting a temporary prepaid plan to finish carrying out my mapping efforts.
So far the only tower in the immediately area I'm aware of on B41 is one on the campus of Jackson State.