a good design system setup with /impeccable init should define your spacing well enough that it's rarely an issue. but occasionally if i want custom spacing or a custom element, i'll take a screenshot of that section and describe in detail how i want it to look.

if it's super detailed i'll use apple dictation to record myself speaking to it. i can go for like 4 minutes describing the change, then ask it to grill me to confirm it understands and surface any edge case questions.