Load mip maps? In short, this is what worked for me:
This fully loads all mips from the start, no delays needed. You can also set this on a per-component basis, so you can have it enabled on just the components that need it (i.e. the ones you see from the start).
You don’t want to use a delay because different computers load at different speeds, so there’s no promise the texture will be fully loaded before the delay is over.