Good day Masters Cecil & Robert I haven't found much on the topic of mirror use in your courses or forum. Do you discuss mirror use in more detail in one of your e-books or elsewhere on Geomancy.net? Thank you once again for your time.
Peace and Prosperity,
Michael

Frankly there are some materials on this subject, but are scattered all over the website:

1. Mirror facing Dining table

Try to use one piece or three pieces instead of two equal sized ones. If we can visualise, two pieces when placed against the dining table is slicing the middle of (or spliting) the middle of the dining table, inauspicious.

2. There are many other exampes of mirrors in a bedroom, facing entranceetc...