Looks real good to me , well organized and you can walk right up and find whatever you are looking for . As far as insulation goes you can buy the insulation in strips and put them in the walls and staple them in place until you are ready to run the wiring and at that point just slip the wiring behind the insulation . A wall covering I have in my paint booth is 1/8 " thick white tile board , it has a semi gloss finish and reflects light real good . On the ceiling you can get 4'x8' sheets of styrofoam and put it on the ceiling and that will help you through the winter and in summer will help with being hot in inside . Good Luck , it looks like you have a very good start .