To safeguard at least one part of my bitcoin vault I have decided to sign a postdated transaction, e.g. three months from now, made with Electrum, addressed to my "hot" Electrum wallet address.

As another security measure I have decided to sign another similar transaction dated a little earlier, addressed to my cold storage address, to prevent spending in case of a potential "5 dollar wrench attack" makes me disclose the original transaction's hash and the "hot" wallet keys to an attacker.

After that being done - to delete the signing wallet file and the seed and make several backups of the transaction's hash including an online encrypted backup, risking some privacy to ensure the transaction's hash is available.

Is there any pitfalls in such a scheme?

Thank you!

P.S.: I think that the "Insufficient Transaction Cost" issue is addressed by the ability to use the "Child Pays For Parent" function in Electrum.
The "Network will change a lot by the time of unlocking" issue is addressed by relatively short period of locking.
The "Necessity to spend some funds" issue is addressed by locking only 1/3 or 1/2 of a vault in such a scheme.
Please correct me if I am wrong.