Well, I've got several track days coming up and my brakes are shot, so time to swap in fresh pads:
6 track days on the old pads.
Here's one of the titanium heat shields. This is the side facing the pistons. Notice the gold color with slight bits of purple. This means that the backing plates on the pads (e.g. caliper side) are reaching approximately 750F (400C). Also notice the uncolored circular regions where the pistons are making contact. I didn't take a picture of the reverse (pad side), but it is solid gold in color with significant purple stripes.
...and done!