Thank you!
> I think the only downside to this approach is that there might be some effect based on time of day or the interval affecting your results.
That is definitely true. I'm about to start alternating the versions every 5m to mitigate this. The closer I can get to 0m, the more accurate the results are. This way even if you get a followers spike (let's say you get a viral tweet), the followers will be properly distributed between each version.