havnt heard the OK1s but i do own a set of PK1s which has been recabled with stock KSC75 cables (as im unlucky enuff to encounter stiffening issues with the ori Yuin cables). i cant really agree with a lot of what u said about PK1s having overwhelming bass nor being sibilant up top but i did find the ori PK1s a tad laidback, slightly unfocused in soundstage/imaging, thin & recessed in the upper mids & are very sensitive to amplification.
with the ori Yuin stiffening issue turning out to be a blessing in disguise, the recabling has made a significant upgrade to the PK1s SQ so much so that most of its weakness are now rectified. driving by a good hicurrent SS discrete home amp, bass is deep & extended with solid definition, mids are grado-like forward & full with smooth detailed highs. soundstage & imaging is alot more precise & lazer-like incomparo with the more blob-like original. infact i've sold an ex Grado SR225 cos i found the properly driven recabled PK1 to be as good if not better - indeed to my ears, the bass is deeper & fuller on the PK1 & the only edge the fullsize SR225s mite have is that its a hair airier. otherwise the recabled PK1 sounded better to my ears, earbuds or not!
besides the need for proper synergistic amplification, perhaps the only other fly in its ointment is the SQ degradation in a noisy environment. in this i would assume the OK1 mite have the advantage. otherwise, there's a lot of life yet in this here "ole" PK1s
