"Gravitational Wave Rockets. Volume 3." provides an in-depth mathematical presentation on methods of approximating general relativistic scale gravitational waves and space-time warpage by modified Fourier Series. Accordingly, Keplerian scale gravitational wave equations are used as basic trigonometric series in modified Fourier series as methods to model space-time compression and expansion. Several specific wave-forms are included within this cutting edge digression. The author presents these approximations as methods to enable increased effective Lorentz factors in virtually light-speed travel with consideration of superluminal travel as combinations of both inertial or translational travel through space and space-time warpage. These proposed approximations can in principle enable enhanced light-speed impulse travel and at least ever-so-slightly superluminal travel. Additionally, Volume 3 includes a rather in-depth first order consideration of several modes of light-speed travel. These include translational travel, quantum teleportation, quantum tunneling, warp-drives, and wormhole transport. Considered concurrently utilized, each of the five modes may be said to correspond to tiers of light-speed. As such, the wholeness of a spacecraft's light-speed travel may lead to runaway infinite increases in spacecraft Lorentz factors, and analogs of Lorentz factors in non-translational light-speed velocity modes. Additionally, Volume 3 explores possibilities that ordinary gravitational waves may have ever-so-slightly superluminal propagation velocities currently beyond the ability to measure with contemporary technologies. Further still, Volume 3 includes speculative content on the size of infinities per se and how such extreme infinities may manifest Lorentz factors for light-speed spacecraft. I hope you will enjoy the read.