It was very interesting to learn that shading on a landscape panel is more desirable than shading a portrait panel. Most of the residential installs that I have done the panels were portrait, I wonder if it would be better to have all panels put down in landscape so any shading would have less of an effect on production?
It is best to just put the PV where there is no shading or at least very little.
You do not see people mounting landscape on residential rooftops so that shading will only kick in one bypass diode per module. I remember meeting a guy in Canada that was adamant about mounting landscape for this reason. I wonder what he is up to.
The reason we usually mount portrait is because the rails go perpendicular to the rafters and the PV goes perpendicular to the rails for strong PV systems that have been known to hold a roof together during a hurricane.