If you don't trust our prover (as you should not!), you can run your own prover using the server folder in our repository: zk-node-server. You can run this set up locally or remotely -- know that you will need a lot of RAM and disk to be able to run the proving server. Once you have the docker container running locally, you can spin a copy of the frontend locally (more instructions in zkaffold-eth) and edit the value of backendUrl to use your own backend.
If you'd like to deploy your own zk airdrop up to a million people, all you need to do is change the merkle root and the message you have users sign ('zk-airdrop' for us), and redeploy our code. We precalculate the hours-long memory-intensive zkey computation for you, and the rest of the logic works out-of-the-box.
To set up your own airdrop, you can simply put the list of addresses in this list and use the value of the obtained merkle tree root as a deployment argument to your contract (our own script is here). Next, you'll want to edit the message claim hash. To do so, choose a different message and edit the value here and here. Use the hash generated by the circuit as the respective deploy arguments.
Feel free to contact us if you have any trouble with any of these steps.