I just use a low profile jack with a hockey puck under the right rear jacking point. That gives me access to both of the oil drain bolts. I'm only under the car briefly to undo the bolts so the risk of the car falling is pretty small. I used to jack from the rear using a hockey puck on the engine block but it obstructed access to the rear drain plug.
Once the plugs are out and the oil draining into separate pans I lower the car and go do something else for 20-30mins to let all the oil drain out.

 

Takes a split second for disaster to strike. Please please always use some sort of stand.

 

Great solution. I've got a set of Rhino ramps that have to be pushing 18 years old.....They are stored indoors, but the safest thing to do would probably be to scrap them. Wood might be heavier - but it does not crush.