I was interested by the handwriting comment: I write very much as a right-handed person would, but left handed, so apparently I am right-brain dominant. I play guitar left handed.

Mike, who I play with, is left handed but writes somewhat more crabwise (left brain dominant?) and plays guitar right handed.

It appears we are both picking with the hand opposite the dominant brain side.....

Someone once suggested to me that you should use your dominant hand for picking on the guitar since it is better suited to rhythm and tempo. So why do you operate the basses on an accordion/melodeon with the other hand?

BTW, as a lefty I have taught guitar to right handed people by siting opposite them and working a mirror-image thing.