Keep in mind that a 30-degree edge will easily outcut a 40-degree edge. Since Spyderco says your current edges are 30-degree edges, let me ask you a question: are you currently seeing problems with the edge chipping out, indenting, or rolling inordinately? If so, then go up to 40-degree edges. But if not, there's absolutely no reason to lose performance to go up to 40-degrees. Never go up to a higher angle unless you really need to! Your edge will tell you if it wants a higher angle or not, so listen to it.
If you like your knives to cut well, the edge angle strategy is: use the absolutely lowest edge you can get that will not sustain damage (chipping, etc.) during your hardest jobs.
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I'll add something else here. I sometimes find it odd that people are so interesting in learning about the different steel choices they can have, but aren't at least as obsessed about making sure they sharpen to bring the best out of each steel. I know folks who have spent the money to buy, say, an M-2 version of an ATS-34-bladed folder. Well, one of the advantages of M-2 version is that it's tougher and stronger than ATS-34 version. That means you can take the M-2 edge thinner for better performance, but still not have to worry about edge damage. In other words, if you're going to spend extra money for the M-2 version, but you're going to keep the edge angle identical to the ATS-34 version, then to some extent you're wasting your money, because you're not getting all the performance out of the M-2 that you should.
Given a relatively tougher or stronger blade steel (and heat treat), you should be tailoring your sharpening to that steel, otherwise you are absolutely not seeing what that steel can really do.
