If it's hard to tell where the bevel starts and the flat of the blade ends it sounds like you are doing something wrong in the grinding or the finishing of the blade to be honest. There should be a crisp, clear "grind line" at the back of the bevel (and it should be an even distance from the edge all the way along).
A possible causes of it not being crisp and clearly defined are that you are rounding it off during grinding or finishing. You need to keep both the flat of the blade AND the flat of the bevel, erm... flat. This way there will be a clear line between them as they are at different angles. If you let your abrasive run from one to the other it will blur the line between the two areas and your blade won't look right.
