I was able to complete this work in 2 hours 30 minutes, most of which was spent fine-tuning and checking for any errors I made. The work itself is made of four layers, and I used the erase tool, the quick select tool and the Layering Option to complete this.
I used the eye dropper tool to match the correct colors for the blending. I then used the brush to mark the areas where the colors were the purest, leaving a small space where I could blend them together. I then used the eye dropper again to blend two colors, and used the air brush tool to fade the lines where the colors gradually changed.