~ remaining 8 characters at a combined speed of 400Mkeys/s, over Discord. The estimated runtime is 16 days. ~
These numbers don't look correct.
With 8 missing characters it should take less than 4 days (1/4 the reported runtime) to check all permutations.
58^8= 128,063,081,718,016 / 400,000,000 k/s = 320,157 s = 3.7 days
That's because he wasn't sure that the "w" at the beginning of "Kw" was correct so he wanted to check Kw, Kx, Ky and Kz just to be sure.