But should there be a minimum amount of hours flown?

Why would you put a minimum number of hours on it?

The CFI has his reputation and certificate on the line whenever he
solos a student -- this, alone, is a sufficient consequence to assure
that no one is soloed too soon, IMHO.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"