I think the system that was used for Assemble would work well, with one change: not using emojis. The emojis were fun, but it wasn't disclosed what they were for, and there were so many emojis. Not sure how it looked on the judges' side, but I assume it was difficult to sort through the projects and assign categories.
Instead, we could make a cookie 🍪 system, where each participant gets a number of cookies (maybe 50?). They can assign as many cookies as they want to other projects, and judges can sort the list by cookies and assign the final awards.
One thing this loses is the categorization effect of the emojis, but judges will also be able to see the projects, so they can probably think of the best projects for each award pretty easily.
The ship cards from Assemble were really cool! But my potato camera was unable to detect the red QR (and installing a dedicated QR scanner creates friction), plus my phone didn't support NFT so that did not work :/ I'd suggest having the actual voting link somewhere on the card, as well as using a black and white QR code to make sure it works for everyone. (Yes, the ID was on the card, but it wasn't apparent what the link was.) And hopefully connection pooling is implemented ;-)
Not sure who the Assemble judges were, but I'd assume they could include Hack Club Staff, students part of the organizing team, and maybe some randomly selected attendees? Probably ~10 people would be good, but would love to hear what worked/didn't work at Assemble.