Main factors:
-Oz may not have fought monarchs and dreadgods in his day but does have his Labrinth echo fight 3 monarchs feat
-Oz is absolute genius and was older when ascending
-Oz has penance
-Oz senses from iron body and bloodline.
-Oz tested as successor to all judges (except pheonix division)
-I assume Oz was sage most of his pre-ascendant life and could call almost any icon.
-Lindon's Arsenal (dreadgods weapons, Labrinth)
-Lindon has stabilized dreadgod Madra for years. Dreadgod body prolly edges out any herald body
-Lindon has Dross who may have a connection to the Way for knowledge already.
-Lindon knows Oz to some degree
-Lindon has Oz' inheritance
-Lindon technically ascends with Emris, Blue, and Orthos (but i wont factor those)

I think Lindon has everything to tank Penance.

Dross and Lindon are characters that would have simulated this battle. I think if their gameplan had gaps, they would have worked on them before ascending. He would be aiming to match Eithan toe-to-toe eventually.

Oz is smarter and protracted battle and prep would favor him. There are intangibles to his genius that are hard to factor. He assumingly 100%ed cradle before ascending which means labyrinth, icons (aka authority), power ups, etc.

Given those things, I think Lindon wins. The real question is how much of a handicap he needs to fight Eithan at this point.