I would go for the single bevel flexicut, it was designed for fan carving and after using one I prefer it to anything else.
I have also made my own from 1inch wide bandsaw blades, grind the teeth off and grind in a single bevel and hone sharp. Put a couple of handles on the end and away you go.
From my experience not only are you riving the wood but you are also cutting it. I know that a double bevel tool does not work well on some woods, but if you are using a good straight grain slow gown pine a double bevel will work. The ultimate is to get the wings or fans a thin as possible 0.70mm is about my average.
I have also made my own from 1inch wide bandsaw blades, grind the teeth off and grind in a single bevel and hone sharp. Put a couple of handles on the end and away you go.
From my experience not only are you riving the wood but you are also cutting it. I know that a double bevel tool does not work well on some woods, but if you are using a good straight grain slow gown pine a double bevel will work. The ultimate is to get the wings or fans a thin as possible 0.70mm is about my average.