Bending the float is not a good idea. Many times when restoring a Zenith I have had to discard the float because it was so badly molested it would not close the valve properly. Adding or subtracting washers is the way to go. However, my experience has been that a new unmolested float will close the valve properly at the 5\8" nominal level with just one washer under the valve.
To set the float level accurately the best method is to have a test stand that will not only visibly show the level where the valve closes, it can also be monitored over a period of time to see if it will hold at the level.
A float stand can be fairly simple. You can even mount a glass jar under the top casting while it is on the car and see where the level is. The various suppliers sell a device that screws into the drain plug that has a clear tube that indicates the float level. I never had any luck with them though, so I built a test stand. It has been used at numerous club seminars over the years. Photos attached.
Tom Endy