Sliding Door track cap

Sliding Door Roller Rail

I'm trying to repair my sliding doors, and I think I have found the right rollers, so this is about putting a track cap on the roller rail. The track as it is is not in too bad a shape, but for the sake of my wife I want it to be as smooth and as easy to open as it can be. I don't think a picture would be of much use so I am going to try to describe it.

I will describe the rail from an end view with the exterior of the house on your left. The height of the rail is 5/8" on the exterior side and 1/2" on the interior side. I think this was done to keep water from standing under the door. The top of the rail is slightly rounded and is 3/16" wide, and measuring downward from the crown of the rounded top, it steps inward twice on each,side in the first 1/4" down. Then, on the interior side it goes straight down to the bottom. On the exterior side is goes down to a depth equal to the interior side, steps slightly out, and goes on down to the exterior bottom, probably 1/8" at most.

The door is installed now without rollers, and I notice it is now sitting on the bottom of the interior side. As it now sits there is a little over 3/4" clearance above the top of the door. I am hopeful I can use the small rail cap. Any advice appreciated.