If you have a wide enough ramp, this approach works well for us. The goal is to keep the boat trailer visible to the driver out of his driver's window as long as possible on its way down to the water. If someone is driving the boat to the trailer at the same time as you are backing, loading can be done very quickly.
Launching is the same way. ALWAYS begin the curved launch track with the driver side of the truck on the water side so you can watch the trailer make its arc towards the ramp.
The driver ALWAYS approaches the ramp from the passenger side so his window is facing the water. He passes up the ramp and them begins an arcing path to the water.
