What kind of volunteer hours are service schools looking for?

GPA is the limiting factor here. Failed out of college 10 years ago. GPA since has been better, 3.7 in the last 60 credits, but I’m aiming for the service schools because I’ve already got 5k in clinical hours.

My volunteer time isn’t there yet and I’m trying to get a sense of what they want to see. 500 hours? 300? 1000? What would people consider kind of the minimum amount of volunteer time to have a shot at one of these schools with otherwise mediocre stats?