Ok, sorry to have been slow making this available, but this is how I would line up the points on the midterm to letter grades. Note too that I pushed it up a little bit in order to exclude (2e).

47–50 = A, 43–46 = A−,
39–42 = B+, 35–38 = B, 31–34 = B−,
27–30 = C+, 23–26 = C, 19–22 = C−.

This is perhaps better than you might have anticipated, if you think of 60% as the cutoff for passing—but it’s far too difficult to try to design a test that is exactly the right difficulty level to make the percentages line up that way. The scaling I give above pretty well reflects the actual nature of the test I think.

As for how you are doing overall at this point, I’ll try to work up a kind of midterm estimate within a day or two. You can kind of figure it out based on the scale above, dropping a homework, etc., though the scale for the midterm and the scale for the homework will be slightly different to reflect their differences in difficulty. So, soon, on that. I’ll make it a visible column on the Blackboard site when it is ready.