After reading through this thread, my thoughts on the ethics of prepping for tests in general run along these lines:
1. If the test materials are indicated as secret by the publisher, it's not OK to prep specifically for that test.
2....
5. It's always OK to teach thinking skills. So, for example, the mere presence of analogies on different types of tests doesn't mean one can't expose a child to analogies. For another example, over-the-top stressful hothousing of things like vocabulary wouldn't be unethical test prep, though it would be bad parenting.
6. It's always OK to practice test-taking in general, to lower stress levels etc.
(7. The fact that test prep will inevitably happen to some degree is a compelling reason not to rely just on numbers from one type of test, or maybe any types of preppable tests.)
From page 15:
Prepare the students for the test... If at all possible, go over the directions for the test�especially those with unfamiliar item formats such as matrices�a day or two before the test. Make up additional practice items to ensure that ALL children understand what they are supposed to do. NEVER start the test unless you are sure that the children understand what they are supposed to do.
From all of this, I conclude that the Mercer Publishing materials are okay to use too. The test publisher seems to allow publication by third parties of extensive study materials, and insists that students be exposed not only to the rules of the test, but even practice questions, at least days in advance of a test.