Good effort. I wasn't aware they were planning on not using much of the upper bowl but it stands to reason as it's so far away.
As you point out though, the front row behind the goal is 20m from the goal line. And the incline of the stand is lower than at a "football" stadium, so for every row you go back you're further away.
There's a reason Juve hated the Delli Alpi, it was shit in every way. And ill bet you anything you want, west ham fans will wish they'd stayed put before the first seasons over.