Hi doneydonydone,
in my humble opinion there is no real need to use a 4096²-terrain unless using a DEM (for highest reality).
TGTP is adding (if wished) with the heightfieldshader fractal detail to any loaded .ter
As soon as you are displacements for overhangs and so on, the detail is only limited by the smallest-scale in the fractal shader.
Regards,
Volker Harun