Thanks for the tip. I'll be sure to lap it carefully.
A bevel setter seemed like a good investment. A step up from wet & dry paper and lapping film - although some people do seem to use these successfully. The softer Super Stone is probably all I need for occasional bevel-setting v the faster Naniwa Pro.
I'm hoping a few laps on the 10k once a week or so will maintain an edge for months at a time (plus stropping, of course). Lapping film would work too but, as it wears down, the "bite" is less consistent. On the other hand a stone is less consistently flat as it wears down... well, maybe if you don't lap often enough.
I think the Super Stone 10k is almost as fine as 1u lapping film. With lather and a light touch, maybe all the way to 1u? I prefer a mild edge so this could be as sharp as I ever want to go. If I do need more there's always CrOx and FeOx on balsa.