bookshelf speakers on the floor

If it works for you, that is fine. For giggles you might try different heights until you find the sweet spot. 

In high school my friend Chip had his KLH 6’s on the floor. His system was a Pioneer receiver and a Pioneer belt-drive TT. Listening to Buffalo Springfield, Traffic’s John Barleycorn, Pink Floyd’s Ummagumma ... was quite an experience! 

You could try decoupling them from the floor with something like Nobsound springs. This will clean up the bass and open up the sound for a more spacious soundstage and focused imaging. Putting them directly on the floor accentuates the bass effect but can also muddy it by vibrating the floor. If you feel they sound better with the springs but lacking the previously colored bass, you might add a small sub or two like the REL T5x.

Typically you want the tweeter at ear level. I wouldn’t be surprised I’d very short stands might be optimal… but as said. Ultimately experimenting will tell. Toe in and tilt will influence directness of treble and soundstage.