I will say, the foam rings DO make a difference in all around performance of the roller. I installed them just now, and there is no leakage around the fleece like before. I hope it extends the time between roll changes.
leakage around the hole is very minimal, and I agree that the ring that comes with the klir does not fit perfectly. The gasket is extremely thin, any movement bumping will cause leakage. I just lift up the klir slightly while sticking the gasket to match the ring and set it back in place. Only takes a second.