Yes I know this is a horrible idea and not BIP39 compliant, but please help satisfy my curiosity with this "thought experiment" and applied maths exercise.
Two questions, one for 12 words, the other for 24.
Assuming "perfectly random" entropy to start, and yes the final checksum word gets changed with the new ordering, not itself included in the alphabetical sort.
Just how much entropy is lost in the phrase's re-sorting, compared to the original random sort?
I don't need the "show your work" maths, more like practically speaking about current brute-forcing capabilities, "you would lose 70% of your entropy, and 40% respectively"
If not too inconvenient, something ELI5 like, how many supercomputer-years of effort's difference?