If anyone is looking for a flicker-free floodlight, the "PHILIPS LED 120W PAR38 3000K 1200 Lumen 13W Dimmable Flicker-Free" bulbs have virtually no flicker. They are currently $31 for a 4-pack on Amazon
Using the "(max - min) / max" formula, these have 0.3% flicker. I bought five boxes (20 bulbs) and all of them had roughly the same amount of flicker.
FYI, they are quite bright (1200 lumen). They use 16 individual LEDs, so if you wanted them not as bright you could try popping off the lid with a knife and break one or more of the LEDs inside. I don't know whether they'd flicker if you used a dimmer switch.
Here's a couple screen shots. Showing 8000 mv as the total light output:
Showing 25 mv as the range (equivalent to max-min):
