Both methods would need to be adjusted each time a new item is added/removed.
The spacer method would involve some configuration updates when the number of items changes. The Gallery could still reference content either Dynamically (including my item tag) or Manually. Each time an update is made to the number of items, an update to the spacing would also be needed to keep it current.
With the customized card method, a new card would need to be created via HTML/CSS for each new item.
-Rylee