Sorry to let this stagnate for months, but I can confirm that an NVidia GPU which exposes 32768 as a limit for Vulkan will still refuse to create d3d12 textures with a dimension larger than 16384, even with feature level 12.1. (And it still exposes 16384 as a limit for d3d9). Given that, I think the right thing to do is just add a test that the limit is no higher than 16384, and probably also cap this in wined3d rather than ddraw.