Maybe if I try to clarify a little bit further as far as to what I'm trying to do exactly it might be able to give us a better picture of whether it's feasible or not.
I fully understand what you are trying to achieve.
Specifically what I'm trying to do is print out a list of the 2048 bip39 words and randomly select 12 to create my own offline generated seed. Can this be feasibly done?
If you select 12 words, there's a big probability that your seed phrase doesn't pass the checksum.
Instead, you can select 11 words and then try to find a word which lead to a valid BIP39 seed phrase. By valid, I mean it passes the checksum
This is completely feasible, but it's not a common method for generating a seed phrase.
If you insist in generating your seed phrase in this way, you should make sure that the words are picked 100% random.