The nylon washers I bought were 1/8" thick, I had to sand 1 down to get to fit. Also the door check bar want to "naturally" sit on the top so I went with it, otherwise it was a perfect fit.
Love it. What sort of bolt is that, and what material? This would get rid of the habit of those pins to close up on their seams and start the check arm clacking.
Any chance it was a 6mm hole originally? Just guessing. Also, how did you get it in? Even with the angled end of the pin I still have a hell of a time sometimes.