Running a Trezor CoinJoin on Bitcoin Testnet tonight

I went ahead and grabbed the newest Suite and Firmware and loaded up bitcoin testnet to give it a shot (for free). Here's the basic setup... If you are online tonight, jump into the join by doing the same. Join should cook overnight. I'll post results when it's done.

BTW: I'm doing this on testnet because I'm not a big spender. Want to see the process run end to end before I commit real money to it. Call me cautious. Since there is so little traffic on testnet, I can't guarantee this will work. If you want to dive straight in on mainnet, feel free. Just follow the guide using mainnet instead.

1. Download v23.4.2 of Trezor Suite
2. Verify download using GPG
3. Install Trezor Suite v23.4.2
4. Verify your have your Trezor-T seed using a dry-run recovery
5. Launch Trezor Suite and upgrade Trezor-T firmware
6. Enable Bitcoin Testnet on Trezor Suite
7. Send some worthless tBTC to your Trezor using a faucet here, or here
8. Read the zkSNACKs Terms of Service
9. Perform coinjoin on Testnet

Fee estimation / guestimation

In my test I started with 1m sat. I choose the default options which suggested 5 sat/vB and 30 rounds. The way I choose to calculate the fees was:

``` given: cord_fee = 0.003; max_fee = 5; rounds = 30; avg_vB = 250

final_est = principle * (1 - cord_fee) - (max_fee * rounds * avg_vB) final_est = 1_034_443 * (1 - 0.003) - (5 * 30 * 250) final_est = 993_839 ```

My first attempt was with only 25k sat and that failed to reach the proper anonymity level (5). The second attempt was with 1m sat.

My avg_vB is too high (obviously) but the process shows why small amounts are overly expensive. You can do the same calculation for say 2m sat and it doesn't look nearly as bad. I'm just 1 hour into the coinjoin, so I'll let you know how it goes. I did this on a burner account, so here are the addresses and transactions so far. I'll update throughout the night as the coinjoin cooks.