Make it a newer skin, one that's been updated to the latest "3G" standard (my term, "3rd generation").
while I think that skinning one of the older skins provides very valuable experience that will serve you well in the long run, it's also harder because of many flaws in the skins and how they wrap the bitmaps onto the plane shapes.
I would suggest BMF is hard to pull off if you have no experience. It took me several tries to come up with a decent system, and that's after I already had a dozen skins under my belt.
If you can, choose a skin that is painted (camo, OD, whatever) for a new model plane. Try one that isn't full up if you actually want to submit. If you're just practicing, choose any plane you like.