Looking for opinions...I recently took a position which may require shooting no further than 500 yards. Most of my shots will come from 100 yards or less. I'm not in the process of searching for a spotting scope and have come up with three options - GR 20-60X80MM, SX-5 SANTIAM HD 27-55X80MM STRAIGHT and MARK 4 12-40X60MM TMR (all Leupold). Any thoughts/suggestions would be appreciated. Thank you!