I've been away from model railroading for about 30 years and I'm building a new HO layout.  The finished project will be about 4' X 20'.  I going to use EZ Command, but I was wondering if I should divide the layout into power districts (or blocks as some call it).  The DVD and manual that came with the EZ Command doesn't really say much about it - only a quick little blurb about turning all power districts on before turning the unit on.  Any suggestions?              Thank, Jerry