What type of gear ratio should i use for my lift which is a dumper. I was thinking about 1:5
That should be a good place to start for this game. Depends on how long the arm is and how much weight you want to lift.
The one trick comes in making the small gear not skip. The length of the shaft between brace points has to be limited so the shaft does not bend.
The other trick is make sure you have rubber bands or black elastic bands to add extra lifting power on your lift. That way the motor is concerned with moving the arm versus lifting all that weight.