Noses are not that complicated
and come in quite a variety. The ones I have the most success
with are oval circles.
I use the nose in two different
situations: First, I put the eyeballs right next to the nose, butted
up to or having the nose overlap the eyes. I can do this with
the (A) and (C). Second, I have the eyes over the nose with no
overlapping--this is good for nose (B), because of the opening.
You have to experiment and find a face you like and that fits your character.
If you notice in the example
I've used two half-circles combined with an oval to create his nose.
This face would be good for a 5" round balloon.
Here are more
examples for you to try.