SBL212 -
i saw someone recommend you use the 17 degree angle. if you choose to, be VERY careful. when i was younger, i destroyed a knife trying to use that angle.
personally, i wouldn't recommend anything under 25 unless you're a surgeon and sharpening your scapel.
ETA - pay attention to where you clamp the thing (can't remember what it's called) on. use a reference point on the blade, that you can remember, so you put it on the same position each time
if you have the "deluxe" kit with all five stones. start with the extra coarse and create your own edge rather than hoping to match the factory's