With a Perl script I generate numerous Google Line Charts for 20 and more series of data at once.
The legend labels are of the form: a serial number appended by an i
To get full legend in your chart just add chartArea width and height as below
var options = {
title: csv,
width: 800,
height: 600,
chartArea: { width: "50%", height: "70%" }
};
Take a look at this jqfaq.com to get a working sample
in chartArea, make width 30 percent move the graph to the center.
chartArea: { width: "30%", height: "50%" }