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.
bookshelf speakers on the floor
I spend a lot of the time on the floor (bad back) and read, listen, waste all the good remaining hours of the day like a lazy cat. I tried a pair of speakers on the floor, - before moving to a stand - and noticed that they sounded better than on a stand - to my ears. When I am on the floor, they sound even better. (Yes, there are a number of things wrong with me)
Is it OK for a bookshelf speaker to be on the floor? And if so, should I put something underneath? (Should I try putting it on my stomach? Just kidding!)