I decided to simplify things by using one-point perspective. I set up a grid on my paper, complete with horizon line, vanishing point, and stationary point (at least two times as far away as the outer limit of the sketch from the vp) so that I could determine the depth of the square grid. Then I started drawing the bases of the glasses on the grid. I still need some work here, but now I know what to study next.
I just eyeballed the tops of the glasses and their curves. That will be study for another day.
After all this thinking and staring at empty glasses, I felt the urge for a little reward. Cheers!
p.s. If anyone has suggestions for simply drawing glasses that look accurate, I'm eager to know them!