PT yes you get a tiny amps flow right to the end. I don't know what Phil is on about. Maybe he already bought a mono panel! :)
You can get voltage input to the MPPT controller anytime with your meter--it is supposed to be Vmp less voltage drop, which the MPPT controller itself sets and keeps adjusting.
I usually see in the order of 29v at the controller (panel rated Vmp is 30v) and 29.3v at the other end of the wire out at the panel.
What is hard to get for me is what Imp is at the time so I can tell what watts are at the controller input. My controller only shows the output watts.
In the same way you can just get more panel for flat vs tilted, I suppose you could get more mono vs poly if the money worked out. Of course more panels that are all "asleep" won't help much! :)