that’s a great idea, in addition you can create an interface in the beacon where player can select the amount of blocks to be protected, instead of putting them in different sizes which can be a lot, just put them in different shapes and the player can select the size he want from the beacon interface.
Also, to restrict player from claiming the whole land, you can put a block limit for every account (example- a player can claim up to 90 blocks) and the amount of blocks that can be claimed increases the more the player play the game (example- 10 minutes = 1 block add’ed to your claimable blocks).
It will give the players another reason to stay online 🙂
hmmm maybe player can also trade/sell those extra blocks they have in their inventory that they accumulate over time.
One last thing, the protection should include everything from the sky limit down to the earth core because some people love to build long towers or underground base.