An alternative to the Cobra approach and one that may look more 1950s is to think about Golden Ratios. See -
http://en.m.wikipedia.org/wiki/Golden_ratio
A 5 - 3 - 5 stripe/gap sequence will be close enough, and very pleasing to the eye. Your current configuration will make the eye want to check that the gap in the middle is the same width as the stripes.