I've had canvassers and have had a hard time retaining. They do great at first but seem on the look out for better things. I've paid £10 per hour plus commission and got problems.
I've found them starting late, finishing early, getting the minimum expected then stopping for chats, pricing things wrong, making promises and not telling me, not passing on customer requirements like days gates unlocked or best times to call back, not checking for conservatories then pricing wrong and taking down details for commission. I've been through a few. All ex energy company guys!
No one can do it better than you. You also get a feel for the area so you can sense the right areas to bump up the prices
Danny