Tbh im super super paywall editor won't support centering vertically and surprised example paywalls are basically hardcoded heights and won't look good when switched to tablet screen preview. The paywall editor is lacking option to centre element in available screen height. Take any example of the paywall, switch to tablet screen preview and you'll see everything anchored to top of the screen instead centred vertically to take full available screen height...

Reproduce easily: create empty paywall → add features element and try to center it vertically in available space - theres no way to do it as element spacing cannot be set to fill height because “can't fill width - parent element set to Fit”. But parent element is simply paywall element without option to adjust this setting. Setting height to pixels. 

Without feature of entering element in available space its not possible to build properly reactive UI adapting to different screen heights