"It's no secret that hi output Japanese engines maintain excellent cylinder sealing for 200K miles and beyond, what rings do they use?"

Toyota OE rings are cast and they last forever. I'm at an independent now and we use Hastings with good success.

'54 3100-235-T5 trans-12 bolt 3:31
'68 Impala 307/350
'78 Sportster/Original owner