VoiceOver and limited vision approaches for custom stepper control

I have a product for designing particle emitters, which I suspect may be of limited interest to people with limited vision.

I'd still like to ensure I'm doing a good job with VoiceOver mode.

There's a related, simplified sample online, if you want to look at the code

As you can see from the picture below, a large part of the interface mimics Xcode's particle editor, with many value entry controls that combine up/down buttons with a tappable label. Tapping the label goes into edit mode.

Apart from changing how labels are stepped through in voiceover in my app, how should I handle these stepper buttons? Is this a good place to use a Custom Rotor?

VoiceOver and limited vision approaches for custom stepper control
 
 
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