Manifold Studio allows you to create a snapshot of your collectors for any of your Manifold Creator contracts. To do so, simply head over to your contract settings:
Bellow you'll see a new option called schedule snapshot.
Once you schedule the snapshot, it will show up on your home page with status "Running". Snapshots usually take around 30 minutes to run.
Once your snapshot is complete, you can then use it for ERC-1155 airdrops: