Even if you mount the USMC kabar almost at the very tip (i.e. the last part of the "flat" part of the blade just before the false edge and primary grind begin) you still will remove a good bit of metal near the tip... I have found it to be unavoidable, however, finding the sweetspot definitely helped minimize it. It is because the thickness of the steel near the tip is much greater than the rest of the edge in my opinion.
The easiest way for determining the angle, especially when starting out, is to match (or as close as you can), the bevel that is already on the knife. From there, you can decide how to adjust it, depending on how you use the knife. This page shows one method of doing this... How to Find your Angle.
As for taking off too much metal near the tip, adjusting the knife horizontally, will help control this. See this page... Finding the Sweet Spot.
thanks everyone for getting back to me, i really appreciate it, i'll keep the angle the same on either side from now on, and do you guys think 20 degrees is a good angle for the Benchmade 5000? And do you guys have any tricks or recomendations for degree and where to set my USMC Ka-Bar on WE, i did it at 20 but it takes way to much of the metal off the top inch and a half or more of the blade near tip, any feedback is much appreciated, i tried checking blade database but didnt see these two...