How to calculate 3X income rule for section 8 and Minimum credit score

[Kadia Lawrence]

If you have a minumum multiplier to qualify people on income, e.g., income must be 3X rent, how do you make the calculation for a tenant using a section 8 voucher?

Also, if you are using one standard set of criteria to review all tenants, both section 8 and non-section 8, do you require a minimum credit score? If so what level do you use?  (I am debating where and whether to reset a credit score miminum.  I would rather focus on the details of the credit report (such as collections and delinquencies and nature of those issues).)