The official 42mm Apple Watch display is 312px x 390px.
https://developer.apple.com/design/human-interface-guidelines/watchos/visual-design/display-sizes/
Some design resources such as Sketch and Adobe files are using arbitrary sizes such as 352px x 430px and 440px x 520px and so on.
Even the smartwatchkit UI Kit from the official Adobe Xd blog doesn't use the real dimensions 312px x 390px.
https://theblog.adobe.com/additional-ui-kits-adobe-xd/
So...what's the convention regarding device sizes during design and prototyping?
https://developer.apple.com/design/human-interface-guidelines/watchos/visual-design/display-sizes/
Some design resources such as Sketch and Adobe files are using arbitrary sizes such as 352px x 430px and 440px x 520px and so on.
Even the smartwatchkit UI Kit from the official Adobe Xd blog doesn't use the real dimensions 312px x 390px.
https://theblog.adobe.com/additional-ui-kits-adobe-xd/
So...what's the convention regarding device sizes during design and prototyping?