On solitary vs teacher-student, since I am still viewing this as a very simple issue, I would say the answer would likely be either.
Either alone, or with a teacher (and I can certainly see that advantages of having a teacher or at least a friend to talk to) the way to reason through any situation would be to turn the possibilities over in your mind and identify them as best you can. For a very obvious example, when evaluating which course of several to apply, sitting down and preparing a chart of the pluses and minus of each option. Which brings to mind that i still like at time today to use a pen and paper to write things down, and I find that the act of writing seems to solidify my connection with the thought. People talk about that as muscle memory or something,right? Maybe there's something analogous about visualizing that also helps make the issues real.