Found this article about the number of time each Championship team was on Sky last season. Sunderland, at 19, appeared the most and Burnley were on 18 times. So your estimate of 30 not on TV is a good guess.
https://www.birminghamworld.uk/sport/football/west-brom/how-many-west-brom-games-shown-sky-sports-compared-middlesbrough-norwich-city-millwall-4139946
Next question is whether they allow multiple log ins on one account - my son is away in college. Can we both watch the same game on one subscription? I doubt it but will ask them.