LCD Topgun Distance and Calibration

[churwitz]

I just bought an LCD topgun and am trying to calibrate it and use it with MAME32. Have red a number of posts that say the distance to stand away from the monitor (27 inches in my case) shouldn't be too bad - around 5 feet. However, I stand 6.5 feet back and I still cannot seem to hit the right hand edge of the screen (left hand seems fine)

I've read about high powered LEDs or mounting the LEDs horizontally. Anyone got any more information about that? Why would horizontal mounting help?

Any other opinions as to why the left side of the screen can't be calibrated?

[moriartyds]

If you have a 4:3 monitor or heck even a 16:9, the top of the screen  is closer to the bottom than the sides are to each other.  Thus if you mount the LED's horizontally you can make them closer than if you mount them vertically.  Since the distance you have to stand back is related to the distance the LED's are apart (less = better), mounting them horizontally should allow you to stand closer to the screen.