As far as Soartex, iirc the 1.10.2 builds of IC2 haven't added that much in the way of new textures compared to 1.7.10, you could probably re-use textures from an older Soartex download. You might need to fix some filenames/paths and copy some model and blockstate jsons from the ic2 jar assets folder to get them working, but that shouldn't be as bad as making completely new textures.
I'm doing textures for the machines right now since I don't like BDCraft and soartex much. I will upload it as soon as I get more than a few machines done. Right now it's 512x512 but I do plan on down-scaling it to 256x256 so it will not slow my laptop to much if I want to play on it. But since I only just started making textures I'm not sure if it's something you would end up using.
You might need to fix some filenames/paths and copy some model and blockstate jsons from the ic2 jar assets folder to get them working, but that shouldn't be as bad as making completely new textures.
By some it's probably nearly all of them, a lot of textures were shifted about when converting to models. On the plus side, I don't think you have to include the json files with resource packs if you're not changing the models, it will use IC2's if a resource pack doesn't include it's own.