My challenge now is suspending the gate on rollers keeping it aligned top and bottom at opposite ends. I guess this is more a problem of a moving target due to the soil shifting the fence around.
Three years ago I installed the 6 foot fence and last fall I pulled up the west 70 foot side to set the post deeper hoping it will stay straight this time.
In 70 feet the top was meandering 6 inches. String line when installed.
Pisses me off.

Rolling the gate on a track will line the bottom up. I figure I'll have to make a large "V" at the top to guide the gate closed.