basement pod lights

Hi,

I want to install some pod lights in my basement, and would like to know how many I should install and at what distance from each other. the dimension of the room is 18 feet 8 inch by 13 feet 8 inch. I will be puting drop ceilling, and the heiht of the ceilling will be around 7 feet. This area will be use as a play room for my little girl and movie room for us, therefor will be installing a dimmer switch. I found the type of pod lights that I will be using, there are 4 inch round pot lights. Also will be buying these Energizer PAR20 LED bulbs.

http://www.canadiantire.ca/AST/brow.../Energizer+PAR20+LED+Light+Bulb.jsp?locale=en

With this info, can you guys tell me:
1- How many pod lights should be installed
2- How far apart should the pod lights be installed from each other
3- How far apart should the pod lights be installed from the walls

Thanks