I do the hard washer in the bolt recess as well. These I want to be 'zero problems' or '100% reliable without a doubt' 'to last like OEM' for Randall. Not that the washers become an issue, just that this is not a max effort port job. We are about waist deep. 10 more cfm would be chest deep... and you gotta ask if you handle the disappointment if it hits a water jacket or head bolt..
I do that too. These heads are meant to be as reliable as OEM without a doubt, nothing special needed , and the last thing to blame if something fails.. lol