Trust me, it gets easier. Like I said, I'm sure there are some cheaper options out there. I know that many use command line tools to edit data. What area are you working with?
I use a program called Global Mapper to cut up the geotiff's and convert them to png's. If you edit the geotiff's in PS, I "think" they lose their geodata. There are other ways to edit geotiff's and have them retain their geo reference data. Chris, I'm sure can shed some light on it. I do know there's a plugin for PS that does all of that but it ain't cheap. As to the question of exclusions, you are correct.
That's the big thing to me that I learned the hard way while experimenting with different airports and imagery. Go ahead and download more than what you THINK you need so you don't have to go back and do it again.
One thing you can try is to make a mosaic of your tiles in PS, then create some layer masks to help adjust hue, saturation, levels, etc. Once you get the desired results, crop away.