Regarding the OP's question on the Oneway system:
1. I agree with Roger W's comments that the two middle sized knives are the more useful ones. The small one is also good if you have a valuable piece of wood, like a burl. I've made a few bowls with the largest knife, but I still have them (they are too big for my outlets. Others' experiences may vary.)
2. I purchased carbide cutters to replace the HSS ones that Oneway supplies. I've been very happy, have cored many bowls with no resharpening needed yet. I got mine from AZ Carbide.
https://azcarbide.com/product/1way-c...arbide-cutter/