Originally Posted by gamgee 
Could you please explain workflow a bit more - how did you do it?
Usually, I'm "try and error" kind of guy, but clock is ticking on me and I don't have too much time for experimenting.
I'll apreciate any help, thank you.
This was not a fast way to do it, but I just opened all the files in Photoshop and pasted them onto a new canvas.
I then jigged them around, using the free transform tool to get them to align as closely as possible. Set the opacity of the layer you are working on low enough that you can see through it to the one below, and after that, it really is just experimentation until you get something that looks close to right.
It truly was a PITA, and I wasn't able to get everything right.
I was trying to put a map back together, and by the time I was done, the country wasn't quite the right shape.
I didn't know that, but the guy who gave me the job certainly was willing to point it out to me.