The conscious mind should be the first to use.
When we are learning new things, we put in conscious effort to research, analyse, reason and memorise. These are the functions of our conscious mind.
After some time of repeating the actions, we do it more effortlessly. The subconscious mind does the work for us automatically.
The same applies to remember new faces. First you make a conscious remembering using whatever method, and your subconscious mind surface it to you the next time you want to recall.
The same when you go for a tour. You consciously take in the images of the things, people and places. They then enter into the subconscious mind as memory. You recall using your subconscious mind.