Structuring Creative Finance Deals

[Spencer Greogory]

I am looking for some help in structuring creative finance deals and want to understand possible balloon payments. 

How much should I keep the down payment at?

Should I offer above asking price and how much above?

How low of an interest rate should I offer with the deal or should I even offer any with offering above asking?

How much of a gap should there be between when it comes to the payment to the seller and the possible rental income the property could produce?