If I am not wrong Sham tested the 5/8k stones and said good things about them. But Sham has a ton of experience with honing and can get max out of a hone, unlike a person just starting to hone.

As Robin pointed out learn shaving techniques, razor maintenance, and touch up to keep your razor in shape before jumping into honing.

If you really want to hone, get a shave ready razor for your shaves, and a vintage razor from eBay or antique store to learn on, using your shave ready razor as a baseline to compare against.