I started doing panos recently and want to buy tools to help produce the best results
Before you start spending money on a pano bracket, check out, how often you had problem stitching the pano due to parallax error. It is a relevant issue for example indoor; it may or may not be an issue outdoor.
You can make lots and lots of excellent panos even hand-held. If you have problems, shoot from a tripod. Note, that the plate of swiweling/rotation should be be level, not the camera itself. If there is problem with the stitching or with the result, post it.
If you are really into panos, then spending on the stitcher is more important than the pano bracket (and it costs much less). Decent stitchers are those, which are based on Panorama Tools: PTGui, PTAssembler, Hugin (I am not sure about Autopano Pro).
How close does the subject need to be for a pano head to be of benefit?
The problem arizes, when the very same close subject appears in several shots. Otherwise it is often no problem at all. The following example was shot hand-held, from a rock in the water, only a tiny bit above the water level, between the tree you can see at the left edge and the shrub at the right edge. These both were not too big, they fitted in one single frame (each), thus the stitching did not cause any problem.Pano with 28mm lens on 1.6x cropping camera