~snip
I've tested the tool a few times and it's a nice idea behind its use. First make sure to select a random block hash from any of the latest blocks the tool automatically does the rest of it. Depending on the randomisation of the outcome of the block hash , that is how the winner is selected.
There is a max of 30 that can be filled in the toolbox, whereas he has 64 users to draw from.
I suggest he runs in batch, in batches of 3 separately, after which the winners from each batch should be redone to get only 3 top users from the giveaway tool.
3 users from Batch 1, Batch 2, and Batch 3. A total of 9 users, then use the tool again to get the last 3 winners.
Edit: Valid from Hosemary.