I decided to do some more time checks with my POV code.  As a

Yeah, I call that the next revision of FastSPI … some time in August …

And actually, you could do that kind of stuff outside of the library.

In your loop method:

void loop() {
static CMinWait<500> waiter;

//… load stuff

waiter.wait();

//… show stuff

waiter.mark();
}

Huh, that’s definitely worth a try!