Do you realize what an anomaly the Olympic 800 was? I can guarantee it's not going to go freaking 1:14 through 600 this year. Rudisha himself even said that he didn't want to race Moscow the same way he did London. And he's hurt still and so is Amos. Very very likely the final will be won in 1:43.pt. No one will be able to solo like Rudisha did. The only reason everyone else ran so fast is because he was a world record pace rabbit for the whole field, and he was probably good for close to 1:40 flat if someone took him through 400-500 on pace.
No way in any other race except the Olympic final does Amos run 1:41.7, and he won't even be in it. So again, I wouldn't be worried about anyone soloing a sub 1:42 for the win. Not gonna happen.
Solomon will probably get excited, take it out in 49 flat and then get devoured. Symmonds for silver. a 1:43 race is gonna be perfect for him if he's in 1:42.mid shape.