Here is my 2 cents and a word of caution from someone who has been there:
It is wise that your loan policy reflects the same definitions as your adverse action reasons. For example, if you use length of employment as a reason for turndown, it might be wise to include an unacceptable or acceptable time for length of employment.
Also, if you use debt to income as a reason for denial, be sure that you have some type of work sheet to prove it to examiners.
Recently, we received a complaint....a customer was denied a loan based on debt to income. The customer was clearly a poor risk, however, we had no work sheet proving the method used by the loan officer to calculated the debt to income.
When I received the complaint, I asked for the loan file and began to calculate the debt to income. I found it to be in accordance with our policy. The loan officer was new to our bank and was not able to arrive at the same debt to income figure listed in his loan documentation. Additionally, he had not read all of the income records or read them wrong...................Anyway...........
This proved to be very sticky...needless to say.... 
Good luck