DIY speaker stands

Usually in that case you want to be at midBass axis. Tweeter below tips the lobe upwards.

dave
So how does that translate into the recommended stand height for seated listening to small bookshelf speakers, say for example 13" or 14" tall, when the tweeter is located above the woofer as compared to when it is located below the woofer? Let's say for purposes of discussion that your ear in the seated position is 36" from the floor. What should the stand height be for both cases?
 
Wherever they sound best.

How tall is your seat? how big the room? Listening distance? What exactly does the particular bookshelf 2-way lobing look like (depends on driver spacing, XO frequency, slopes, how it blends with the natural response of the drivers)?

https://www.prosoundtraining.com/2013/01/25/tweeter-placement-two-way-loudspeakers/https://audiojudgement.com/speaker-lobing-polar-response/
For tweeter below flip the MT upside down.

dave
So, it seems like it really doesn't make that much difference in the sound whether the tweeter is above or below the woofer if you are seated with your ear at about the same height as the midpoint between them. Is that a pretty accurate statement?