You'll need a closing date and time for entries otherwise you could get a lot of entries at 9.59pm on the 27th lol....
Also, I know it increases your postage cost but I would do 1 pack for the 4 closest guesses and that way you will get 4 x the sampling and hopefully the reviews.
Also, I know it increases your postage cost but I would do 1 pack for the 4 closest guesses and that way you will get 4 x the sampling and hopefully the reviews.