Also can be found under the Hilti Brand at HD. Have to do Vertical with the toggle cause its many times a C channel and can't install horizontal.

If you are using a low profile bracket, similar to the Snap Razor, you won't be able to install toggles in the top and bottom holes on the wall plate. The toggles would overlap since the top and bottom holes are so close together. Not to mention you aren't leaving that much steel between both holes. I then installed the toggle bolts in the sheetrock only for the bottom row, on the last TV I did.

I have used a magnet to locate the studs and then use a thin drill to find the edges of the studs so that I can drill the Toggler Hole centered.

You can use a stud finder on the electrical setting to help check for voltage lines.

Thank you. I don't know why, but I didn't think about Ernie when I replied.

I hope you meant that you used the top row on the mount.

Since we're talking about torque or lever type load over a TV mounting plate, if only one row on the mount can be used, top row should be used.

Top row uses the Togglers through the metal studs.
Bottom row is togglers to drywall only in mounting holes offfset to to the metal studs, since if you try to drill another set through the metal stud, for the bottom holes, the togglers would overlap vertically.

Right, and best.

The back piece of the toggler is about two inches long. What mount has top and bottom mount holes about two inches apart? The closest ones I can remember having seen is about four inches. For them to overlap, the mount would have to have top and bottom. Also, you could put the togglers in with the back pieces slightly tipped off the vertical so they wouldn't overlap.

The forces on a TV mount can be thought of this way: If the TV were to move, it would move in two ways. It would move down the wall (shear force), and both upper and lower bolts prevent this; and it would pull off the wall (pullout force), where the upper bolts, then the lower bolts, would be pulled out. While the TV mount is solid on the wall, the pullout force of the top lower bolts actually creates a pushing force on the lower bolts, helping them hold the mount in place.

Many LCD low profile mounts, have 1 row of holes for mounting. Others like the
Snap Razor Style Mounts
[Link: snapav.com]

and even the Peerless ultra low profile Mounts [Link: peerless-av.com]

have top and bottom holes which are very close together. I ran into this issue when I used the Snap mount on a metal stud wall in a commercial office space.  I tried to offset the togglers but couldn't do it to gain enough space to fit both. The back piece of the toggler is wide enough that you can only offset slightly by the time you hit the edge of the stud. Also, with the holes so close together I figured I was killing any structural integrity of metal stud with leaving like 1/2" of material between upper and lower holes.