I'm a complete noob to the security camera world, but I like the Hikvision 2432 based on all the positive reviews. However, I have a couple questions before buying. The room is approximately 11' wide x 13' long. I assume I'm going to mount on the far wall. Based on this, where exactly should I mount and then what lens am I looking for 2.8, 4 or 6mm? Thanks in advance for any help you can provide this noob!