Just an update, finished the job today!

Rented the "EZ Trencher" and it worked like a charm. Holy crap did that save a ton of time. Worked as advertised, the only thing is my speaker wire spool was to large for the spindle so we had to lay it out first but it wasn't a problem

Highly recommend it if anyone needs it!

Ill post pics of the trench size as soon as i upload them to photobucket