Roland Keyboard Club have an excellent set of articles about different keying pattern to use with the Guitar Mode. They might help you.....

As to the E60 being 90% G70, be careful using that description. Half the polyphony, no Vocalist, only 2 Upper and one Lower Part, no Direct Outputs, no FC-7 pedal input, no extra Footswitch input (basically, no foot control at all other than sustain and volume) no VK organ section, no color touchscreen (B&W only), etc., etc..

There is a reason it's a LOT less expensive! But at it's price, I'm sure it is a VERY capable arranger, and one of the few choices for those of us that need a 76 note keyboard.