[Imp]

Suffice to say LOS from a level 1 hill places you just below single story building roof height, You cant see over it even to another level 1 hill.
Level 1.5 (slope) you can just see over it if its reasonably close.
The higher you are & or the closer the obstacle the better view & as these increase your angle of view down hence reducing the number of blind hexes produced, the converse is also true.
Luckily the game does all the maths for you working out the viewing angle & hence blind hexes produced.
Its not hard & you know the hex size so could do it yourself but it would be very time consuming.
The easist way to see how it works is find a wall in RL to look over & change your height & distance from it.