I guess this is a love or hate kinda thing. I love Freehand Profits work. Would I buy one? No. Do I think the idea is creative and original? Absolutely. He has mad skills.
Hmmmm... For the parts that are leather I would recommend that you prep it with cotton balls and acetone, removing the factory coat. You can lightly wipe the hyperfuse parts of the upper as well to remove the waxy factory finish. Then you will want to tape off the parts you do not wish to paint...
First off, Do. not. use. SANDPAPER! Use as said above by ddh, cotton balls with acetone. Sandpaper will cause damage to the area it is applied too. Also, I use AngelusDirect.com I find it is cheaper and it is ran by sneaker customizers/restorers like you and I. If you have any questions feel...