3D printing assistance

I hope that I've chosen a good section of this forum. I need some assistance with 3D printing. I'm a complete newbie at this topic, so that I would appreciate any advice.
Nonetheless, I'm not sure what is the best software to design and save it in .stl format. I,ve been recently experimenting with DesignSpark and SkettchUp. Is this good enough?

I want to make simple black mask with holes for eyes, nostrils and mouth. It will be similar to Jabbawockeez or popular Guy Fawkes mask. Am I expecting too much from 3D printer? Anybody have done that before? Which dimensions would be the most versatile? 6 or 6.5 inch wide head?

http://www.thingiverse.com/thing:430883
http://s14.postimg.org/v7ggb41ch/img_thing.jpg
http://s16.postimg.org/75mtmljt1/HOT...alloween_f.jpg

Explanation mark: I am able only to design one thing, save as .stl and send it to the man who will print this by himself.
Thanks in advance, peers!

This doesn't sound like a project that would be particularly hard to print. But you need to find some software that will let you design it without too much trouble. I'm not sure that either of those programs are really intended for that sort of thing. They both are focused on mechanical types of parts; what you need is something that's intended for organic modeling. If you're limiting yourself to free programs, look at something like Blender, or Sculptris.

Andrew Werby
www.computersculpture.com