I know that feeling mate, got the clutch waiting to go in to the ute but been working 6 days since the rona started off. Leaving the ute alone for a bit and racking up the OT, hard to say no when it's there.
You'll need a 20+ psi cap. A 16psi that is used on the standard overflow isn't enough on the hot side. I've got a tridon lever cap from super cheap. The branding comes off to leave an alloy plate on the cap wich looks pretty good.