I find that its a waste of time in my area to image anything below 45 degrees due to pollution/refraction. Is it okay to limit APPM to above 45 degrees or will the model be improved by modelling below 45 degrees even though I won't be imaging there?

Also, I'm at a .49arc/sec image scale - should I bin my ML16200 to 2x2? Haven't in the past with an image scale of .44.