Turns out I was missing one of the 3mm screws in the Tekin kit. Nevertheless, they were too short to use with the Grid mount anyway. If you're using a Grid mount, I suggest you go get M3 x 10mm and M4 x 10mm screws and not use the Tekin hardware (except to install the fan).

As for the pinion, I'd just use Hot Bodies, as suggested by Grid and be done with it. That way, if you're using the stock mount and upgrade to the Grid mount later, you can still use your pinions.