I’m sure I have mentioned this before, but the stock Warmoth truss rod cover is just ridiculously HUGE!!! Not only that, but it has three screws to hold it on. Like that piece of plastic is holding the whole guitar together! I honestly see no reason for it. One screw is enough. Juxtapose that with the rear rout cover that’s easily ten times the size, and it only has four screws. It’s just comical.
I would just take the stock cover and use a belt sander to take the meat off the sides. Leave the screw hole at the top. You’re finished piece doesn’t need to be more than 3/4” - 7/8” wide.