If you don't want to reprofile the edge, go with the 40, it's fine.
With the 30, you will have to reprofile the edge a little thinner(takes some work) You may want the diamond rods for this(or an Edge Pro).
I like a little thinner cutting edge, so I reprofiled and now use the 30 deg and it cuts like a laser.:thumbup:
I reprofiled my Sebenza's edge on the Sharpmaker initially at 30 deg. inclusive, but finished the edge at 40 inclusive. I needed to remove obtuse "shoulders" from the edge bevels as they came out of the box. It took quite a lot of work, on and off, over some period of time, until I was satisfied with it (I only had the white and grey rods, no diamond rods). Although my bevels are still convex, and might always be to some extent, they are much thinner than they were originally.
If your edge bevels are not as thick as mine originally came, then 40 inclusive alone may be fine.
Although I had previously completely reprofiled an extremely dull old ATS-34 version Benchmade Stryker, reprofiling my Seb, though a long task, gave me lots of added confidence in sharpening/reprofiling. And I did not find the S30V steel to be any more difficult to work than most other steels, personally, once the thick bevel "shoulders" were reprofiled away.
Because, like the deal with the A2/1-piece controversy, Chris feels that his chosen cocktail of blade steel, heat treat, profile and grind geometry strikes an optimum balance for the broad market.
Obviously the Sebenza can be made to slice much better than it does out of the box by simply laying back the secondary bevels. Huge gains in slicing ability can be made if one is willing to give up some durability.
Remember that Chris has to warrantee these blades, so he's going to take a more moderate position. I'm sure there are also some folks who want a little more robust edge, so starting out thick/obtuse allows them to have that.
Personally, I find that I like to drop the secondary bevels down a pretty good bit, but I leave the primaries alone. A better compromise IMO. A Kreined Sebenza would cut circles around mine, but would also be a little too delicate for some of the things I use the knife for - for example, pulling staples.
Neither of my Sebenzas would sharpen well on the Sharpmakers 20* half when I got them. They had to have been more obtuse than 20* out of the box.
I re profiled on a Gatco system using the 19* setting and maintain the edge with the Sharpmaker's 20* half. I get a very slight micro bevel. It will shave hair, and lasts a long time compared to other steels.