Salut,
I sought the number ideal of squares to download with Aeroscenery.
I started with 1 square on the areas where I have sea and land.
as I retouching all the images one by one. My folder .png file contains about 15 images and I quickly finished a small area.
By if I have 100-200 images in folder,the number of .png that I must retouched is high, I find it more stimulating as well.
On the other hand for the flat areas or without relief I will do by 3 squares.
I tried with 6 squares and but it depresses me a little .. to have too many images for an area has retouched.
Then when I check the area on a square or 3 it will be faster to test.
That said, it's a big job, but it's also rewarding to fly to a region where it fits your wishes.
here are some examples of retouching.
I find the ranking of images by sector very important, because later to make the autogen here will be much easier and faster, and to check the area.