Door knockers pay

I assume a lot of you use this method.

Was just wondering how you guys do it:

  1. Hourly rate? If so how much?
  2. Incentive or commision? I just get my guys to find people who want an estimate and then I swing by and give the estimate when he is done door knocking - for this lead I pay $5 each lead.
  3. How long do you let them go for?
  4. How many at a time is most efficient for you?