1 Don Birchett 4 months ago I was looking at the Strings by Mail site and they have a custom set as ordered by a customer "Phillip." This set has the two unison courses with different gauges of string. So instead of have 10-10 or 09-09 they pair a 09 with a 10 and a 12 with a 13. I would think that this would give the two strings a slightly different sound and add to the fullness. Any thoughts?