We're talking about Penrites fully synthetic product right? Is there any issue with that potentially leaking past the Verada seals because it's thinner than the hybrid?

As for the flush, I understand that stuff converts the oil so it easily runs out of the engine... Will it all drain out tho, won't some stay in there? I'm thinking I should flush it, refill and then drain it again?
Also, what's the risk of damaging the engine while that stuffs in there and it's idling? If the viscosity drops it cant protect the moving parts?