I'm buying an Aimpoint soon, and am looking at a mounting system for it, but I'm not sure which height I need. Should I get an ARMS throwlever mount, a cantilever from GG&G or LaRue?

Which Aimpoint mount should I pick? I have YHM flip BUIS, the forward sight mounts on the rail on the gasblock, the rear is a standard YHM flip sight.
I want to make sure I don't end up mounting it too high for the sights.

Quoted: I'm buying an Aimpoint soon, and am looking at a mounting system for it, but I'm not sure which height I need. Should I get an ARMS throwlever mount, a cantilever from GG&G or LaRue? Which Aimpoint mount should I pick? I have YHM flip BUIS, the forward sight mounts on the rail on the gasblock, the rear is a standard YHM flip sight. I want to make sure I don't end up mounting it too high for the sights.

Any of the 3 you mentioned will do. If you decide to get the ARMS, make sure its the one with a riser.

Quoted: I want to make sure I don't end up mounting it too high for the sights.

All iron sights are at the same height, or at least close enough to the same height that it doesn't have any impact on cowitnessing.  With that in mind, any mount designed to attach directly to an AR upper will work for you.  The only difference is that some of them put the dot at the exact same height as the irons while others put the dot just slightly higher so you can still use the irons through the optic but allowing a better view through the optic while looking over the irons.

Like eye-spy said, any of the three will work.  I personally prefer the Larue.