Its a bit off a chicken - egg situation

Who was first.
So it depends on the maps you have or dont have.
I put 4 stones in the area i have the maps for with the right level. (you have 16 stones so new influence you only get on 4 stone area's)
If i dont have the maps i put 3 stones in de area before or next to it and map until i get the map drop required in the 4 stone area.
One importent thing in this strategy is that you have done all the magic and rare maps. That way you increase de drops of higher level maps.
And as you collect more stones divide them over the other area's.
If you have all area's socketed and assume the game decide to drop a level 3 map and you dont have a lvl 3 map available on youre atlas then no map drops at all.
Opposite is true also. If you only have low level maps available on your atlas the possibility a low level map will drop is very high.
The drop of +1 and +2 maps against the map level youre in increases with the atlas completion.
I follewed this strategy and it works like a charm
https://www.youtube.com/watch?v=tEiOuv9xLbwPersonally i believe the breakpoint is around 20 stones. Then you dont have to worry about high level map drops at all.
And do you youre zana daily. Its a source of maps also. And if i experienced it well the level of maps she sells also goes up with the completed maps count.
And like Slayerofasz said you only need the right level maps to get the influence. Use lower maps to get the conqueror spawn.
It saves you high level maps to get the influence.