I have Ortofon silver leads as well and still have problem with its stiffness. I think the problem is worse for Koetsu because of the long body and relatively small room between
end of cartridge and headshell lead terminals. Silver leads just does not like to stay bent and exert quite a bit of force back at the cartridge. Since Arche mounting plate is basically attached to headshell through a hinge, headshell leads kept pushing mounting down at an angle always.I can't keep it perfectly parallel to the headshell.
For Koetsu, I really need something softer than silver leads, I think. All 3 that I have, Oyaide, Ortofon and Ikeda are all very stiff. I just found Acrolink 8N copper headshell leads that looks promising. If it sounds as good as its 8N phono cable, I think it should be ok. Too bad, I really like Oyaide silver lead wires but it just does not work with this particular setup.