DJ

I need to replace my clutch, I plan on getting the stock one from e bay. I see there is a replacement pilot shaft roller bearing available but it requires machining the flywheel larger. Anyone know anything about it, will it last? What size hole should be turned in the flywheel? Also when resurfacing the flywheel is there any special way of doing it? Seems like I read somewhere the original was not flat and the flywheel should be replaced rather than resurfaced. I am using the stock clutch so I'm wondering if the flywheel should be resurfaced flat with it. Has anyone used the Sachs clutch from e bay?
Thanks
Dave