So, the trick with the step cut is to measure in my opinion. I like to use a rule of thumb of 37.5%, 37.5% and 25% for a three step stone.
I’m other words, if the distance from the culet to the girdle is 4mm I divide that distance up for 1.5mm, 1.5mm and 1mm for each step. I cut my first step, to the 1.5mm measurement and then keep it level around the stone. It’s kind of like leveling the girdle to be honest.
Second step is another 1.5mm and third step (closest to the girdle) for 1mm. I do a similar method on the crown, but the step closest to the table is my most narrow step.
I agree with Alan, by the way. I use diastiks/pandamonium almost exclusively. I keep Crystallite laps for 260 and 600. I rarely use 260 though.
I did two step cut asscher gems this week. I was trying to get you a pic of the steps, but I’m telling you I couldn’t get a good pic to save me. I’ll attach the emerald I did. The pic showed my steps slightly better than the aquamarine. I hope gifs work🤞. I did both stones in this design http://dansstarrgems.com/Design-Chermaign.html
Hope this helps you with cutting step cuts. Once you do it a few times it becomes rote, almost redundant. You’ll get it after a couple tries.