I am a landscaper and do NOT provide irrigation installs,however,I am going to do one for my house later in the fall.I have done much reading,including the tutorials reccomended by some of you here.Everyone seems to agree that bigger is better when it comes to water and main lines,so,heres my question? By the way,I have 55 pounds of pressure and 9 GPM flowing thru 3/4" line. I was thinking of installing a 1 1/2" main line with 1" lines going to each zone? There will be 6 zones. Your opinions will be helpful ,so,thanks in advance!