About the tuck keyword and maximum limit: A player may play or put into play allies beyond their ally limit,…

The word “tuck” in an ability doesn’t inherently indicate a limit or maximum on the associated ability; any limit or maximum on that ability is dictated by the rest of the ability’s wording. Silk/Cindy Moon’s constant ability is worded to allow the player to “tuck” more than 4 cards beneath her, but when they do, they must discard down to 4. While similarities could be drawn between this, the ally limit, and the player side scheme limit, that is unique to the ability itself, and does not impose a universal rule for the usage of “tuck.” When Resource Reserve or Ionic Physiology reach the maximum amount of tucked cards, no more cards can be tucked there; a tucked card would need to be removed first before a new one can be tucked. This is because of how “max”/maximums function in card abilities.