Re: the implication of "only so much
I can't say it better than ems did:
Originally Posted by herbiji
You may not be busy at all right now, but in two hours, you have an obligation. "I only have so much time" in that case would mean "I have these two hours to give you. After that, I'm done."
you have a limit to the time available and after that you will be unable to help them further
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.