First and foremost, thank you for organising this event which allows almost all players to participate. However, the 6 hour restriction may cause an inconvenience to some.
Firstly, it is very unusual to select such a niche time slot for the event in general, especially for weekends which players usually may opt to play at other times.
Due to the tight time slot, some players may not be able to participate, such as shown below in the official forum thread:
Suggested solution and justification:
Create an extra time slot for players whom are unable to play at night
Some players may be able to take advantage of these and play at both time slots. However, based on the rewards, it is not gamebreaking, as the items listed would not break the economy or are bound to characters, therefore abuse may not be possible.
Hope to hear some feedback regarding this request.
Thank you again for organising this and have a good day.