Rubens Theme switching from Davinci

[momossa]

Hi, Is there a way I can customize Rubens without activating it. I am currently running Davinci theme.

 

[Direct Webstore]

Hi, Is there a way I can customize Rubens without activating it.

No

Just activate Rubens and customize it.
Davinci's customisation will not be lost. It is saved. You can switch back to it and all will be as it was.
Likewise with Ruben, after you customise it, it's customisation will also be saved.