Does anybody change their speaker placement with different types of music and bands?

This is actually a very good question. Kudos to the OP for thinking creatively. It may be true, not sure, but you'll find very few people wiling to put in the time and effort to do so. Listening habits, i.e. playing one artist for a week, etc. versus a variety of artists daily, would dictate the (im)practicality of it. 

There is no "perfect" positioning; subjectivity is inherently involved in the home environment. Audiophiles can revisit the seating position as well as the positioning, baffle slope, toe in, etc. of the speakers. 

I know of no one who repositions for each selection played, but in terms of speakers used, a different position for each particular speaker would not be unreasonable. You could always move the listening chair to suit your fancy as a means of getting into or out of the soundstage. 

In my experience I have found that a favorable positioning of the speakers relative to the chair is gratifying with all music. I do occasionally experiment with width, toe in and distance from the chair, as well as speaker distance from head wall.  YMMV

The only fail safe way to find the absolute best locations for speakers is using the speaker placement track on XLO Test CD or similar. All (rpt all) trial and error methods, laser techniques, etc. are only capable of finding local maximums. It’s like looking for a needle in a haystack by guessing. For a given room and speakers there is only one solution to the problem. All other methods are like trying to solve n simultaneous equations in n+x unknowns. And as progress is made with room treatments and tweaks the speaker locations will have to be re-established as needed.

I'll bet Michael Green does.

I have to pull out my speakers every night to listen and find that I place speakers closer together for albums. That seem to be mixed where there is not a lot of soundstaging. Trios that have bass in the middle but recorded so weak that the drums to the right and piano/sax to the left overpower it. Maybe I have not found the perfect placement of my speakers yet? But it is fun moving them around and do consider my set up high end! 

I wonder if I play a mono record that the speakers should be placed wider than with stereo recordings?

just thinking outside the box eventhough it seems in audio setups everybody is my way or the highway! Maybe they are correct lol