Quote from: Beetkoin on Today at 09:15:03 AM

I am concerned about Ian Coleman's tool having the same issue? Maybe not now, but in the future?

Iamcoleman is open source, if used in a safe offline or airgapped devices, then it is safe. If anything happens, it will only be the fault of the user not the Iancoleman HTML file.

Quote from: Beetkoin on Today at 09:15:03 AM

I was wondering if I should shake a dice 256 times to generate my own entropy? Would that be considered more random than Crypto.getRandomValues()?

All I know is that generating seed phrase directly on Iancoleman which follow BIP39 standard is safe, also generating that on an open source wallets like Trezor that follow the BIP39 standard is also safe. If you do not generate the entropy carefully, you can make mistake. You will need to throw coins to right down the binary 256 times, and the result should be as exactly as the coin is tossed.

Quote from: Beetkoin on Today at 09:15:03 AM

Also I realized that the seed phrase can be more than 24 words long?

Less than 12 words seed phrase are not secure, it is not more than 24 words on Iancoleman, but you can make use of passphrase to extent the words, maybe it is what you meant. More than 24 words seed phrase can be gotten, but not Iancoleman, and not on any wallet I have used, it maximum word is 24 unless you extend it with optional passphrase.

Quote from: Beetkoin on Today at 09:15:03 AM

Is this more secure or just overkill?

If it is optional passphrase, it can help especially if attack saw the seed phrase and did not know the passphrase, he will still not be able to access your coins because passphrase generate another seed, keys and addresses entirely.

Quote from: Beetkoin on Today at 09:15:03 AM

By the way, how do you key in your 24 words into Trezor? Say you already have a seed phrase and buy a brand new Trezor. What do you do then? There are only 2 buttons on Trezor right?

To recover back your bitcoin, keys or address
https://blog.trezor.io/learn-about-trezor-recovery-seed-offline-backup-fe235873c69f
https://wiki.trezor.io/User_manual:Advanced_recovery#:~:text=Start%20by%20plugging%20your%20uninitialized,check%20the%20Advanced%20recovery%20checkbox.