We have a number of paint spraying devices,from the cheapo Burgess self-contained type to the more heavy duty units, and all have their purposes. The old Burgess type was advertised for jobs like fence spraying, but we found that the units just were not man enough for the task.
What I would suggest is that you visit Machine Mart if you have one in your area. They carry a fair range of different type of sprayers, plus 'some' of their staff can be very helpful on this subject. If they recommend something that doesn't do the job, then you could request a refund?.