In most cases you should have no more than 2 diopter between your differential and normalized.
1-2 diopters is the range, and going below or above the range can cause slower improvement or even introduce unwanted results. Most people in most cases fall in the 2 diopter range naturally, though some scenarios you may create a larger diopter gap unintentionally.
Here’s the promised video explaining the diopter gap premise and how to best manage it: https://vimeo.com/276391987/eebd78688f
Any issues viewing the video, please let me know. I’ve been using a paid Vimeo subscription rather than free Youtube for BackTo20/20 and now for Le Meow as well. This provides a lot more flexibility on what is available to who, better video quality, and none of the Youtube nonsense. You’ll likely see only this video even though the channel has a whole library (available in BackTo20/20).