I wait every year for this topic to come up. Yes, there is a huge difference between glute soreness and sores developing around the tailbone. A normal C2 seat rubs around the tailbone. Depending on anatomy, rowing style, etc some, maybe most, are not bothered by this. Or they develop tough skin. For others, perhaps the minority, the solution is to make sure that part of the anatomy does not rub on the C2 seat. My technique is to use about a 2 in thick fairly stiff piece of foam the same size as the seat with a U-shape cut out of the back. That raises the tailbone off of the seat. End of problem. There are several who have read my posts about this situation over the years and benefitted.