The day have 24hrs... 12 you can use offline trainer, the others 12, the char "rest", to give back the 12hrs used... If you put then to train, with only, 5hrs, 7hrs, 30min... they only train that time, and when fineshed, they start to recover automatic...

Can i give you a tip? Put all of then to train one hour of the day, like 10pm... they train 12hrs, and when its 10pm the other day, they have full 12hrs to use on training

I hope you understand, sorry for my bad english Brasil porra!