KCK,
I use a SUNRay on my GTP1350 and really enjoy using it. Ir certainly reduce the area and holes I dig. Most times I can dig the coins out on the first opening in the ground. I just got an easy digger and todau in the light rain I was popping coins using the SunRay and digger most came out on the first shot.
I also found several coins in a single hole or withing a few inches using the SunRay. By using the SunRay I did not have to move and I could search an area only limited by the cable of the probe. This allows me to dig more from a single spot. It will find coins withing three inches of the surface and sometime a little deeper I think.
I started using a vibraprobe but wanted more depth. I then was using both for a while until I got a few comments and helpful suggestions on ways to use the SunRay more effectively. Now I do not even take my vibraprobe out of the bag.
So I give the SunRay a big thumbs up.
Farnum