Patrick Chase
A more basic question: Are you making your own floats, or just trying to figure out how to sharpen the ones you have?

The reason I ask is because as with sawtooth geometry, this is one of those cases where different people will have different preferences. Your best bet may be to start with something widely regarded as "reasonable" (for example LN's Williams-designed floats or the Philly planes floats) and then iterate as you sharpen.

Full disclosure: I currently use a mix of L-N and Liogier floats, all at stock angle. I've sharpened the L-N's a couple times, but haven't changed the angles (i.e. I've tried to keep the file in the existing gullets and not twist them at all).