924 rubber new master cylinder upgrade questions, o'ring seals Options

[pneuhyde]

Hi All,
I am trying to install a new 914 rubber MC upgrade kit and am having trouble with the orings in the kit that I assume go on to the fittings to seal at the connection to the master cylinder. Whenever I tighten the fitting it squishes the oring out the side. This is not surprising to me because I have a hydraulic background and know that in hydraulic oring boss fittings the inside of the top of the female thread is chamfered to allow the oring to crush down into the hole and it is then sealed on the top by the fitting. In a metric system that has a flat surface like this cylinder has you use a copper crush gasket for a seal or an oring with a metal ring around the outside that holds the oring from squishing out when tightened.
I would like to hear from people who have installed them and how they solved the oring seal issue - if it was needed?
I have also watched Ian Karr's youtube video and he does not address it...and also, as he admits, the video is done without the front end in place so not near the same view and space as my real world efforts.
Any help will be appreciated.

Thank you,
Steve