Dude ... there was nothing advertised in that video. It was a how-to on removing the lifters, cleaning them with parts cleaner and reassembling them. Nothing was advertised, and of course EcoMike isn't making money on that video. Turn down the volume and calm down. We're just talking here and thinking out loud.
I think EcoMike's idea of soaking with PB sounds safe enough to me, because you're just talking about cranking the motor without starting it. Then drain it, and fill with fresh oil before starting the motor. I would probably pour some oil down the pushrod tubes to help "flush" out the PB.
But I also think this would be my last resort. I would try the M1 5W-30 first. If that didn't work, then the ATF. If that didn't work I'd run the Marvel Mystery oil for 3k miles.
Ultimately, the best approach is to pull the head, fish out the lifters with a magnet, and clean them like in the video. My '91 motor has about 67k miles since rebuild, and I'll probably pull the head at 100k for a valve job. Cleaning the lifters at that time would be a good idea.
EcoMike ... if you try the PB, please let us know how it goes. Thanks for thinking outside the box.