One of the best authoritative sources regarding the use of the Bombe and methods to determine most efficient settings for the Bombe for decoding, is given in the following source:
Enigma: The Battle for the Code
John Wiley & Sons, Incorporated
Several editions of this book are available electronically here. Because the Bombe was ultimately arrayed, the source will provide insight into the processes used. The whole of activity at Bletchley Park was a mathematical and statistical-probabilistic tour de force. This book may not answer all of your questions, but the appendices give excellent insights into the methods used. Be advised: The book is directed toward an audience of general interests, not specifically toward persons with a mathematics background. You may have already reviewed this book.