So just to make sure I have the elevation rules right, when shooting downhill:
1) No lower elevation terrain blocks LOS right? So there are no 'blind spot' hexes when shooting over forest? If so definitely parking all of the union artillery on hills next time =P
Not in this game, no. In future games in the series, where there may be 3 levels of elevation, LOS from the highest to the lowest is blocked if two-plus hexes of the middle elevation intervene.
2) Hills terrain of the same elevation does not block LOS to a lower hex? So there is no 'Plateau Effect'?
There is - that's covered in the bullet "Another hex of the Attacker's level or higher".