mechanism in Birch reduction

at first I wondered why 2 H are added to opposite side of benzene like reaction below. because I could imagine 2 H added right next to each other or 1 C away from each other. 


[![enter image description here](https://i.stack.imgur.com/7Skhf.png)](https://i.stack.imgur.com/7Skhf.png)


so, looking for explanation I saw a molecular orbital of benzene. 
[![enter image description here](https://i.stack.imgur.com/gQBv6.png)](https://i.stack.imgur.com/gQBv6.png)


It's one of LUMO from benzene and from this I just guessed that maybe hydrogen could be added to 2 unpaired p orbitals in the opposite direction.


but when I learned another Birch reduction I got confused again. 
[![enter image description here](https://i.stack.imgur.com/TC6vg.png)](https://i.stack.imgur.com/TC6vg.png)


since the E level of LUMO above would get high, I assumed another LUMO maybe come into play. 
[![enter image description here](https://i.stack.imgur.com/MjBdU.png)](https://i.stack.imgur.com/MjBdU.png)


so from MO right above, I can under stand e- from Na would go to ortho- or meta- position of substituted group. 


And here's my question. why does hydrogen go to ortho position first? 
additionally, why second Hydrogen goes to the opposite side of first-added hydrogen? and I'd really appreciated any correction about my educated guess above.


