Since the gasket fits between the steel washers, why would you need to cut one of them? Just slide the nut and one of the washers back on the torque tube and put the cut gasket between the washers. I'd definitely look into using a nitrile O ring or something more durable than cork as an upgrade to the original gasket material. Super glue will also join cork, if you decide to stay with the original material. The cork can be made more pliable by steaming it or soaking in hot water before installing. That's a trick we used to use to reclaim dried-out cork valve cover gaskets from old gasket sets.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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