Ongoing customization of a portal based on XOOPS.
At every step, I'd explain the requirements & ask for a time estimate; and if we agree on the estimate; I'd ask to start work. I will pay once the work is completed & demoed to me (I will not ask for the code before paying; but, I'd want to see it work from another site)
Needless to say, I expect the person to be very comfortable with all aspects of XOOPS. There is a chance of a longer-term association if everything works out okay. Also, the person will have to sign an NDA.
Intimate knowledge of PHP is absolutely essential.