Spyderco edges are very unforgiving and the weight of the Spyderfly handles makes the blade bite even deeper when you screw up. Also, the large space between the handles of the Spyderfly makes rolling onto the edge or at least "shaving" your thumb much more likely than with standard balis.
Since a trainer version of the Spyderfly probably isn't forthcoming, I'd recommend buying two knives and dulling one permanently. Tape the sides of the blade or use padded vise jaws to prevent marring when you clamp it edge up in your vise. Then, with a fine mill file, draw file the edge until it's at least about 1/32-inch wide. Then get some fine emery paper (220 grit shop rolls work best) and use a shoeshine motion to round the edge. You should also round and polish the tip, because even with a dull edge, the tip can really bite and puncture.
If you have access to a 1X30 or 1X42 belt sander, you can do all this even faster. I prefer slack belt grinding to remove the edge since the belt follows the edge contours better.
Spyderco Special Projects Coordinator
Founder and Lead Instructor, Martial Blade Concepts