Usually a humidity of around 60% is fine for a good shed. Don't worry so much that it all comes off in one piece, as long as it all comes off without you having to mess with the snake. Normally after you see the eyes go "blue" there will be another stage where the snake appears to have gone out of shed and looks normal again, however, it's still in shed. About a day or two after the return to normal appearance they'll shed. If you haven't read this, it's a wonderful link to look at and learn about the whole process...

http://www.ball-pythons.net/forums/s...ad.php?t=28794

Snakes shed when they need to but usually young BP's shed about every 4 to 6 weeks depending on their growth.