I'm working on a global world building project of a tidally locked world. Here's my approach: I make fractally generated heightmaps using a tool called VP planet generator (VPPG). This creates heightmaps of arbitrary detail for the whole planet.
Next, I want to erode them using Wilbur. From my understanding, Wilbur makes realistic terrain at a resolutio. Of about 10-100m per pixel. So for an area of 100x100km a raster image of at least 1000x1000px is needed. Please correct me if I'm wrong.
The planet is only partially surveyed due to the tidal locking, about a about from 10-30° north. That's still about 150 million square km. At a a practical max resolution of 5000x5000 PX that about 592 individual roles of 500 km˛. Of course, not all of these will need to be mapped, but a lot of them will.
I guess the question I have is this: how can I have global, realistically eroded terrain? If a country map map is too large to erode everything at once, how do I split it into multiple tiles and have them match up when put next to each other?

Thanks for any input. Maybe I'm thinking about this way to co plicated.