I've found another interesting text on the Spacetime (Clifford) Algebra.
https://arxiv.org/abs/1411.5002
I want to adapt their formalism to the 4d case and beyond.
For an EM wave in a vacuum, the authors use this equation:
∂ F = ∂ · F(x) + ∂ ∧ F(x) = 0
Where F is the Electromagnetic Bivector:*
F = E1e01 E2e02 E3e03 + B12e12 + B13e13 + B23e23
And ∂ is the first derivative (with respect to space and time): ( d/dt; d/dx1; d/dx2; d/dx3).
Now this can be generalized to higher dimensions:
For 4d:
F = E1e01 E2e02 E3e03 + E4e04 + B12e12 + B13e13 + B14e14 + B23e23 + ...
(4 electric components, 6 magnetic components)
*In this formalism both electric and magnetic field are bivectors.
Some other Clifford Algebra-based formalisms use scalars for time, and vectors for space, and thus have electric vector E = E1 e1 + E2 e2 + E3
and magnetic bivectors B1 e23 + B2 e13 + B3 e12
(Those approaches do not nicely generalize to the relativist framework, where we could otherwise just model Lorentz Boosts as hyperbolic rotations.)