Nice one Nuttz, looking forward to seeing the results.
Talking about placing tiles over each other reminded me of something. I'm not sure if everyone is aware, If you layer 2 tiles and play with the opacity of the top one you get another 'good' tile instantly, no modification neccesary to the edges or anything.
Simple example below. 1st image is background, 2nd image placed on top with 50% opacity. 3rd image is result. Insta new tile
play with properties, image orientation, blend modes, brightness/contrast and anything else you can think of for sometimes very interesting results.
Gatso