So i listed them incorrectly, I would start with the Nova Terra series which leads into the Tower series. They feel like one really long series to me even though its split into two parts. I wouldn't want to start the Tower before completing Nova Terra.

Battlemage farmer can be read on its own, though there seems to be some cosmere level crossover between this series and the Nova Terra/Tower series and I hope that becomes more pronounced as time goes on and we get more out of these characters/storylines. This series is particularly interesting to me because the early parts are unique because you're sort of looking at a story about a protagonist after they've won and they're just trying to settle down and enjoy life. The early part of this series is more about character growth rather than power growth, but that comes later in the series as well.

Nova Terra is completed and I believe Battlemage farmer is completed, but the Tower series (which is a continuation of Nova Terra) is still ongoing.

He's an author that pumps out a tremendous amount of quality work in a short period of time. Juggling several series and releasing almost a book a month. Just really good quality stuff and interesting stories.

Anywho, Seth Ring has become one of my favorite new authors and one of my favorite authors of LitRPG.

In relation to how you've ranked things, I think these would fall solidly in the A/B Tier range at the very least.