On Gargraves and Ross switches. Atlas and Scaletrack switches are probably the same. Make wood blocks so the ground throws sit at the right height. I drilled holes in the blocks to nail them down with small nails without splitting them.
The ground throws move .280 and the movable rails move .250 so you have to position the ground throws carefully or they wont move the points all the way over on one side.
With the ground throw in the center position and the movable rails in the center position mark with a pencil where to drill the mounting holes. Grind the lead in the pencil down a little so it will fit in the mounting holes.
I had some really small wood screws that fit in the mounting holes of the ground throws. Hardware stores should have them. Rotate the point of a exacto blade to make a center punch starting point for drilling. I used a magnifing glass to be sure I was getting it right as I no longer see real well.
These wood screws are really small so after drilling holes for them run the screws in the holes 1st to make it easier when mounting the ground throws.
If your off .015 or 1/64" then they wont move the movable rails correctly so be accurate in locating the ground threws. I had to glue in a whittled down toothpick once and do it again.