Any recommendation on placement is just a rough guide. The specific location that works the best can only be determined by trial. You can jst try moving the speaker on a somewhat random basis, and in time you will find a good location (this can take quite a long time). Or, you can employ certain methodologies for setting up speakers. The methods that work relatively well include the Wilson method, which emphasizes getting the midrange to sound natural, or the Sumiko method, which focuses on bass response.
I've used the Sumiko method to help set up a number of systems and it works quite well. What is surprising is that bass response can change quite a bit with movement as small as an inch or two. There are many suitable locations that one can find with this method, so one is not trapped into a location that does not work for whatever reason, but, on the other hand, this makes choosing not as simple. What is remarkable is that it is not always the case that closer to the room boundaries, the stronger the bass; there are many nodes such that strong and reasonably even bass can be found in locations well away from the front and side walls (a good thing because imaging is often best with speakers well away from room boundaries).