Utxo management & 12 vs 24 seed phrase

Everyone says the rule of thumb is 1 million + sats or every 1k. Is that still a good rule of thumb or should I stack a little more until sending to hardware wallet?

I just got my hardware wallet the jade plus by Blockstream. Need to set up and test recovery.

Hate to say it but I have 0.50 needing to self custody asap.

Also regarding 12 vs 24 seed phrase which is better?