Hey,
In general I like the idea to make a treasure hunt for the guild. But it shouldn’t be a weekly event, more a daily or a secondary weekly event, which runs beside the normal event.
I think if you make it like this how you suggested, then many players will not be able to play. When this event runs for 7 days and 29 players have to wait, till the first one has done all their turns and then the 2nd etc, then it will lack of organisation and time at the end.
I would make it a way more simple.
You add the normal treasure hunt as guild event. The best date would be, when you have to collect treasure hunt turns at weekly events, like this week now. So players are more motivated to play this event.
The reward could be like all other guildrewards too. You have 8 stages and you have to collect a certain amount of turns to unlock them.
I recognized already from many sides, that treasure hunt is not really liked by people because of the time/reward- ratio.
So if you have a little guildevent beside the main event, you can at least pick up some rewards with unlocking the stages.
I also made a suggestion for treasure hunt in general some weeks ago. Maybe we can bring this topic up again.