Why did you choose 24 words instead of 12 words? If I were you, I would focus on 12 words and would move on 24 words when the risk of future breakthroughs and other types of attacks increases. At the moment 12 words is as safe as 24 for the current technology. To be fair, I suggest to not depend on your memory but since it's your choice and you plan to do it, then I'd suggest you to change your mind and stick with 12 words. 12 words is more likely possible to my mind because it's not much but 24 words are too much. If you are confident in your brain, then do as you wish but be very careful if you plan to save your every Bitcoin there.
It seems the OP has abandoned the topic, and may not return to this forum, so we are discussing this topic without him.
Honestly, 24 words doesn't make that much difference, at least for me, a bitcoin private key has 128 bits of entropy, the same goes for a 12-word mnemonic seed (
]the electrum seed has 132 bits). In other words, if this entropy number is broken one day, not only bitcoin, but also banking and legal security systems are screwed.
12-word seed phrases provide you with 128 bits of entropy. 24-word seed phrases give you 256 bits on entropy. It's easy to see that the security is greater with the latter. However, bitcoin private keys only have 128 bits of entropy. If those ever become vulnerable, Bitcoin is already doomed to fail despite some wallets providing 256 bits on entropy.
In addition, we can extend the mnemonic phrase with a passphrase and exponentially increase the entropy level.
Coming back to the topic of memorizing seeds, we know that it's risky to memorize seeds due to the inherent risks involved, but as long as physical backups aren't neglected or left aside, I don't see a problem in trying to memorize them, since you can restore your wallets anywhere in the world, and you still have your physical backups whenever you need them.