This is how the radiused edge mathed out:
  • Assume a bevel width of around 0.015" (my razors average around 0.008" to 0.015"). Assume a radius of 12' to 24'. The distance from the radiused bevel surface to getting the bevel flat maths out to under 1 millionth of an inch (97 nanoInches to 200 nanoInches).
I would say that any flat hone following a dished hone is cutting the curved radius off to a flat so rapidly that it isn't, in most cases, a practical issue. The info on using a dished Belgian (or any hone) is extremely interesting.

My real worry with dished hones is that changing the spine angle (e.g. to heel leading/trailing) during the stroke will wear either the heel or tip unevenly? I was thinking the operator would have to be extremely consistent to avoid it. Is the dished out portion consistent? It's just so easy to make most hones flat, that I can't see any reason not to do it. Flat avoids all kinds of potential problems. For a new fella' like me anyway.