Hello and thank you for organizing this event!
Check out these two recent retro development events on itch.io:
- GBA Jam 2021: https://itch.io/jam/gbajam21
- Game Boy Competition 2021: https://itch.io/jam/gbcompo21
I think that you may find there some interesting organizational ideas for this Amiga jam, for example:
- they are allowing user donations for prizes and using GitHub for doubling them
- there are bonus prizes for open-source entries (educational value)
- they list coding resources and communities (Discord servers, for instance) to further help participants
- some submissions have built-in web emulators to make checking out games easier
Regards