LOL- Where is the disclaimer label?:
"No Home Depot paint sticks were harmed in the building of this router fence..."
Good job! If you find that the back facing is too tall, you could always rip it down in height, then use interchangable different height curtain faces in front of that, tailored to what you're working on.
Most my router fences are between 3-1/2" to 5-1/2". But, like I suggested, I have various height curtain fences and lots of different thicknessed shims that go between the fence and the curtain faces.
"Don't worry, I saw this work in a cartoon once."
"Usually learning skills and tooling involves a progression of logical steps."