Last night, 5 days after I emailed a request for help/clarification, I got a response from my professor. I shouldn't fault him for effort, as it's clear that he spent a lot of time and effort on his response. The problem is that he didn't answer my very specific questions. In other words, he didn't clarify what I needed clarifying. He answered in many of the same generalities that currently have me entirely lost.
So now comes the calculus. I know students do this all the time, make calculated trade-offs in order to get the best possible return given non-ideal circumstances. I think I'll give the homework one more try, and then I'll just turn it in with the 40% of the problems I have absolutely no clue about undone. Then he'll send me the solution key for the homework, and from that perhaps I will be able to divine some of the clue I'm looking for--because right now I'm clueless. I think that's my best shot right now at not entirely bombing the unit test.