How about this: so a player must reach the required GC rank (let's say second commander or something) to be able to purchase a permit from the GC, then when the player uses it that player will begin queuing for a plot (just like how login queue works), player can see how many players queue in front him by using the in-game timers.

Whenever there is an empty plot is available the game will send a mail to the first player of that queue, that player will have 24 hours to answer the mail that he can either chose to purchase that plot or if that is not the plot he wants then he may pass it for the next player (if possible its also a good idea to let the player chose what specific condition to queue for). And maybe the game can detect if the player receives the mail while online that mail will only have about 2 hours to answer so it could queue a bit faster.

What do you guys think about this, because it's queuing so you don't have to do anything while waiting so this should prevent the situation right now that the player has to clicks spam in front of the placard I'm not sure if anyone had this idea before, this idea just pop out from my mind just now, I think even Ishgard is coming it's probably not gonna stop players spamming in front of the placard without sleeping for days.