I would mount the bars from the ceiling but if you do it from the wall go at least 12 inches to 18 inches especially if you are using par 64's don't wanna burn the wall :P If you go from the ceiling then you can anchor the bar from the beams of the roof and its much easier.
As far as building your own console it sounds cool ! My opinion from past gigs over the years would be try to have at least 4 sub masters or more It makes for less time when it comes to changing scenes. I try to never have the same scene on every song, it makes for a boring show. Good luck !