I was hoping others would chime in for you on this. Doesn't look good for me to be the only one guiding you. Anyone else want to give a hand?
When you come to TDH and look into this part of the forum, at the top are select threads that give very, very, very good advice regarding the leather. The skirting thread even gives a breakdown on cut, sizing, and leather weight. Leather weight can vary depending on how comfortable you are with leatherworking. You want at least a medium to heavyweight so it'll keep it's shape. I'd advise against sole/armor leather as it's tough to work with for someone new at it. The skirting thread also discusses the colors they used to dye Zam leather, though I chose to simplify mine by airbrushing with midnight blue, purple, and a hint of brown-black for the "dirty" places.
Seriously, read those stickied threads. It may take a while to get through them, but there is certain information that I can't really relay to you in a couple of quick posts. There are fantastic images of the actual costume to be found in the gallery section too.