Great ideas Maruromic- have thought about the same.
Something REALLY important, no matter what size rod end is used- and I think the high end $ 3/8ths would be adequate under most conditions, but ABSOLUTELY recommend 1/2" for all other already posted reasons, is the extreme care that MUST be taken in assuring FREEDOM of MOVEMENT of the rod end through the ENTIRE steering cycle. It might mean CAREFULLY bending the steering arm(s), adding washers, and by all means using the CONTOURED safety washers that Mezeire makes. One must make sure t hat there is no BIND in the sytem. Things can break.
Luckily, I didn't lose one of my very best friends twenty years ago in a drag car I'd built for NOT paying attention to the arc the arms go thru and the kingpin inclination.
And we still talk to each other! (Built him three other cars, since).