Yes pretty sure it is Lc. Marie's song. The peloricity is because of the parent Cattleya cherry chip, but it is not a strong peloric parent, peloricity from this plant vanishes in the second generation hybrids. Also variation among siblings can be pretty high, so non pelorics do exist. About the sheath, unless you see the buds in there or atleast a swelling of some sort, do NOT cut the sheath, only if it becomes plump and still doesn't open , should you try cutting the sheath.