Vertical pins in the first 20 minutes and last 20 minutes of hunting hours are misserable IMO. Not enough light to illuminate the pins....looks like one big black vertical line.

With horizontal pins, you can see above, below and to one side of the pin.

With vertical pins, you can see left side and right side. Not above, not below.

When I am hunting, I need to know where that bottomchest line is of a whitetail. I pick my spot approx 6" above thatchest line and let er rip. With additional pins in the way....I can't see that line very well. Quite annoying.