+1 for swapping blades is a bad idea. I tried it once and the result had -5% lockup, as in, the lock didn't even engage. These knives really are hand fit and it is a bad idea to mess with that. That being said, If you are planning on buying a 21 inlay and plain insingo anyways, why not keep them both and have 2 perfect knives? You'll probably end up getting both anyways.