@fly - good leg work and good job on the clear explaination.

@ides - current "truth" is this: "Go as deep as you can, the only exceptions being races up Zoncolan and stuff like that"
The current equations all "prove" this. In 8 years we may have a different "truth", but the moment, the weight of science rests on going as deep practical. That being what we are working off of at the moment, I'd say again,

You won't do better than 1.68s.