Can I pick my own 12-word Recovery, or is it given to me when starting a daedalus wallet?
It is a pre-determined mnemonic. Makes no difference if you had your own dictionary/list of words.
You can create your own 12 word wallet by selecting a valid set of words from this list https://github.com/bitcoin/bips/blob/master/bip-0039/english.txt
Not all combinations of 12 words are valid. The way you can do it is to 1st create wallet normally letting Daedus pick the 12 words. Then create a new wallet with the + sign, select Resotre, and type in the 12 words you want from the list. If the 12 do not allow a wallet, try changing a word until you get a valid list of words. I have accidentally made random wallets doing this (then deleted them).
Afaik you can’t because all selected words to be valid must generate a certain checksum.
More details at Generating mnemonic phrase through CLI
Thru user interface - you cannot. Technically - you can, but should not, because you immediately put your funds under the worst security imaginable, and if something happens to them later - cannot blame wallets for being bad.
In order to make wallet actually secure - it is protected by randomness, not by convenient set of words, and especially not by set of words a user would like, or would find easy to remember.
All wallets give your already ready words, because they are technically designed to generate proper complex randomness. Humans designed for exact opposite - to always find and tend toward patterns, instead of randomness. So a set of words, picked by a human, immediately becomes much easier for other humans to guess )
So - no one can stop you from shooting yourself in the leg. But I would advise not to do so.
I would oppose to that : I am a perfectly dumb human where you could hardly find any intelligent pattern to match against.
Perfectly designed to produce “perfectly dumb” sequences of secret words? Sorry, couldn’t resist )
Exactly ! Homer Simpson style