I just bought a Nikon (VSD) red dot.  I mounted it on top of the carry handle using a mount that fits the groove of the handle.  This puts the sight a little too high for a good cheek weld.  I also want to use the regular open sights without removing the scope.  Need suggestions on what mount would be best for this setup.  I've been looking at the Arms#39A2 but am wondering if this will block too much of the scope. Any suggestions would be appeciated.

When you say you are afraid it will block the scope do you mean the red dot optic is what you're afraid of being blocked by the 39A2?

I have a 30mm red dot mounted almost in the very front of my ARMS 39A2.  absolutely no problems with visibility out of the optic.  I would recommend this setup to anyone wanting to cowitness with a red dot.  

The only issue I have is the top channel of the mount does obscure the rear sight ring a little, so using just the irons is a little more difficult.  But I still think it is great.

Sarge

Yes.  The lower part of the red dot.