I'm working on a drawing schedule for the free time I have

7 to 8 hours minimum

>>2561090
How so? Do you mean 7-8 hours daily or 7-8 hours throughout the week?

>>2561094
daily

>>2561090
>>2561097
really? isn't that excessive?

>>2561074
There is no minimum or maximum time. Do whatever feels right. Probably this means starting small, maybe 30 minutes a day, and increasing it gradually until doing several hours each day feels normal.

It should be pretty obvious when you are drawing and you are going past what you are comfortable with--you will feel less interesting and have to force it more and there will be diminishing returns in what you learn or produce.

If you are a beginner then maybe choosing a book by Bridgman or Vilppu and copying a set number of pages each day would be a good start. Don't forget to do some creative work too and not just studies though.