I think I've settled on an upscaling process, which involves downscaling, dithering, upscaling and the use of anti-aliasing.
Quite pleased with the results.
![Image](https://i.imgur.com/3NKFAfr.png)
Again I wish I could push the in-game resolution of the bustups even further, but oh well.
I do have very high resolution copies of each bustup, but the example I've show is at the resolution of 1024x512.
(It might be a bit compressed too, for web and discord use.)
Thanks.