I replaced my clutch housing as when I pulled my mower apart and restored it, I discovered it was no where near 5/8 anymore. It was about 2mm off.
The guy I bought the clutch off advised me to replace the bearing inside and the spring as well, he fitted the bearing for me.
As far as my statement the clutch feeling tighter, before I changed the clutch parts when the clutch was disengaged my reel would still spin slowly, which I have since worked out must have been from the spring not being 'springy' enough to fully disengage the clutch. Even though I had tried to adjust it

It may have melted from what deejay said, when I fine turned it I wasn't paying attention to whether the cone was making contact with the thrust pad, I was just trying to find the sweet spot where it both engages and disengages.