Ratchet Wheel and Pawl Design

[nomike]

I want to design a tool which uses mechanism of ratchet wheel and pawl.I can't find the information on relationship between ratchet diameter and its rotational angle.
Can someone tell me what the diameter size should be if we want large angle of rotation?Is there any formula that can be used?How about the number of teeth?

@NoMike
Please do not duplicate post. I have deleted the other Post.

[jboggs]

Lay it out and analyze the geometry. Massage it till it works the way you want. Look at this website for all kinds of ratchets including custom-made.
http://www.lowellcorp.com/