I have recently purchased one Llyn idwal, it was freshly lapped around 1k but when I used it, it scratched my blade. After that, I lapped the stone with 15k lapping film with 5k sandpaper between, and it became much more gentle on my blades. This stone was one of the reasons I opened this thread. I think it has much to do with the hardness of the stone. For the softer ones, I don't think it means something, and even less difference it makes when used with slurry. Don't you have problems with the surface tension between the razors and the blade(when they stick together like two pieces of glass with water between them)? For me, it turns the happy honing time into a nightmare.