I have the yrr rotary and recently engraved a large 32 oz tumbler with a pretty tapered bottom to it. I used the end rollers (the adjustable roller that go up and down for wine glasses) to prop it up to keep it from walking. I want to engrave coffee mugs that are like 20 oz or so which don’t have that large taper. Anyway to keep them from walking? Below is a picture of the 32 oz I engraved and the 20 oz I want to engrave. 
Side note since I had to manually move the laser on its x axis for the rotary set up. Whenever I tell it to move to a certain point on the work space it is way off so I have to manually home it each time. I’ve looked through dozens and dozens of forum topics and YouTube videos but can’t seem to find out why. I was an idiot and didn’t save my initial settings so I don’t know if my soft and hard limits were both on by default.
I have the laser master 2 pro and the laser homes with no issues.
If anyone has a picture of their default device settings please send it to me.