People say you hardly need a cradle strap on a Goodtime, as it is so light anyway. However, a leather strap doesn't slip around on your shoulder like a nylon strap will.
After I discovered that the Lakota cradle strap would not work with the Goodtime banjo, I ordered the Neotech Super.
Another option would have been the Huber strap. These cost $72 or so and have permanent loops at the ends. The installation is semi-permanent -- you have to unscrew two J-hooks, one for each strap end. They also sell two lengths (54 or 60), so you need to figure out which you want -- probably play around with some parachute cord before ordering. What is nice about these is that they are clean (tidy) and very secure. No snaps to potentially come loose resulting in a banjo hitting the floor.
There are also a variety of leather straps with fur padding. I figure in Arizona desert heat, the padding may not be a good idea. The Lakota straps are made from American bison leather which is said to be both supple and strong.
You want the strap so it takes some of the weight when you are sitting. When you stand up, the banjo should stay in the same place.
The 5th string tuner should be near your ear -- i.e. the neck should be at a 45 degree angle. If the neck wants to dip, change the attachment point.