Honestly I'd use the edge of the Chosera. But if you want a natural bevel setter, I'd ask Alex Gilmore at thejapanstone.com to cut me a 1" wide piece of fast suita and I'd use a diamond plate to slurry it to get dense slurry. A fast piece of suita slurried this way is capable of setting a bevel even though it's pretty fine, probably about 4k synth equivalent. An alternative might be getting Dan's to cut you a 1" wide fast piece of Washita/soft Arkansas.

Cheers, Steve