Did you look at the Spitfire, I think the shaft is 1/2 on both and the rockers have some right left to them.
If you are doing the engine, pay close attention to the front cam bearing, be sure to pin it after getting the holes in postilion, if no oil to the rockers after oil pressure is up, that bearing has spun.
If you are talking about the nut being jammed against the wall of the adjustment, different story. Get a gram scale and grind out that area, then weigh to get each rocker the same.
Had lots of fun with that engine in the autoX until they put the Honda Civic in the same class. LOL