Q: “What do you think is the better way to go about things for someone who is running mid-pack average lap times for his racing class? A driver/pro coach or a pro school?”
A: Without knowing more about your abilities I can’t say for sure, but I’d suggest a good coach. Rarely is that a bad choice. But a coach is different from a driver who can show you what he/she does and tells you to copy them. A real coach will help you learn how to improve even when you don’t have someone to copy.
If you have a fair bit of experience, most schools are not be able to adapt to your needs well enough. A good coach will adapt to your needs, rather than trying to fit you into a school’s curriculum/schedule.
Having said all that, almost any and all training – whether with a school, an instructor, or pro coach – will make you a better driver.
FYI – I answered a question about selecting a coach here: https://speedsecrets.com/ask-ross/how-do-i-find-select-a-driver-coach/