I've owned several and used a couple professionally, no real spacing issue, other than just a bit more over the course of a roll. I personally would load an empty spool in to the correct side to allow the camera to function as loaded, and I'd burn thru the equivalent of many rolls in on sitting. If it fails then it would have in a few rolls anyway, and you'd be needing a CLA regardless. After those test firings I'd do a test roll and see if that changes it. The C series are fairly heavily greased on the wind mechanism and obviously a good CLA will clean out the old lubricants and be replaced.
It may seem unusual now but back in the day, I'd do 5-8 rolls in one afternoon sitting and at least a dozen or more at a wedding, and I felt I was hardly stressing the camera. At that point in time the C system was falling out of favor, most shooters having gone the Hassy/Bronica interchangeable back SLR route, but all the C series were and are absolute brutes of cameras, designed and built to shoot dozens of rolls day after day. A couple of rolls of test firings certainly won't hurt it and perhaps might help it in the short term, but a CLA is likely required.
