While there's a lot of good material in those "Oral Prep" books, the FAA guidance on practical tests no longer calls for those simple Q&A methods, but rather goes for "situationally based testing." For example, instead of asking you what the VFR weather mins are in Class E airspace, the examiner may ask you whether or not today's weather is good enough to make your planned XC flight under VFR, and how you came to that determination. This will test, in a more realistic manner, not only your rote knowledge of 91.155, but also your ability to apply that knowledge to a practical situation, not to mention your ability to read and interpret all the available weather data, as well as determining from the sectional what airspace you'll be in so you know which paragraph of 91.155 applies along each part of your route. Those old-style Q&A books can't prepare you for that -- only a good instructor familiar with the concept of situationally based testing can.