Thanks for your advice! We ended up using a M7 x 1 Helicoil kit with a 10.5mm long insert. We considered using a Timesert, but since it wasn't a load bearing application and we couldn't find any in stock locally and didn't want to wait for one to be shipped we went with a Helicoil.



I'd definitely recommend using a genuine Helicoil kit for this repair. We first tried using an off brand one and found the grove in the insertion tool wasn't well cut, leading to the tool either stretching or breaking the tang within the first turn or two. The Helicoil insert (with the provided insertion tool) went in flawlessly on the first try.



I'm happy to report that it's been a few days now and there are no signs of leakage from the valve cover gasket, no more oil dripping on the manifold, and the vehicle no longer smells like it's about to catch fire!