With your AF 60mm macro, one thing to keep in mind is the short distance between the front of the lens and the target. This can cause lighting problems and very narrow depth of field requiring small apertures and long shutter speeds. At these very close distances manual focus is required.
Here's a photo taken with my D300 and the AF 60mm focused at about 1/2 life size. It's the head of a 5 3/4" tall Hummel figure. f11 and the front of the lens 5" to the target.
AF60mm at it's closest 1:1 focusing distance without tubes. f11 and 2 7/8" to target.
With the medium sized 20mm tube only. 2 3/8" from front of lens to target.
With the longest 36mm tube only. 1 3/4" from lens front to target.
The tubes can be stacked to get in even closer but now you'll be very close to the target.
I prefer to use my tubes with longer focal length lenses to get further from the target. It also gives me better, more even, lighting if I use a ring light attached to the front of the lens.