I have to wait at the moment for the SLS2 package, but I will add a example scan later.
1. My used stepping motor was the SMC12056 12V 0,6A from conrad.de. I don't used a gear and coupled the table directly to the motor.
2. I chooses the 1/8 step-mode and the table speed 8. When the speed became to fast, or the step mode smaller I had missing steps especially with a higher load on the table. Thats why I changed the micro switches to the slowest movement (i think both are off in my setup). I tried a lot with the micro switch and the step mode and delay time because it was important for me that the objects on the table are as steady as possible.
3. I used a 9V power supply for the board instead of 12V.
4. I ordered a heat sink for the pololu but I don't applied it on the board because I had no cooling-paste available. I checked the heat of the chip often and it was not too hot in my opinion. I also checked the heat of the motor and it became warm but not more than 60 degrees.
5. You explained every step very well so no shortcomings on your side. The program is very self explaining and just awesome. A bit problematic could be the choice of the motor, because the strength is very important in my opinion to not generate missing steps. I had some problems with the screen first, because I added the 3,6 Ohm resistant with an LCD with already integrated resistant so the background light was of. But I figured it out very soon
I would highlight that a gear ratio could really improve the turntable because the biggest problem I see is the swing time of an object after it was turned on the table. For that anybody should check the delay-time after turning. In my example I changed it to 2 seconds. In addition I had some issues with the displayed angle, after I changed the micro switches. After a 45 degree turn it showed 90 degrees and so on, so I had to change the mathematics for the current angle from 0.9 to 1.8. But with the great explanation inside the code everybody is able to rethink this formulas.