Lines shrink over time. if the manual says 100cm then that's what it should be.

made custom line (same length as i removed, so 90cm) of some maybe pre stretched rope (i just took most strongest rope by feel in shop) & some small inox pulleys
did test today, works fine additional i did minor mixer tunings and i'm pretty satisfied how it flies.

but to replace pulley, you need to remove whole C gallery, that's 8 ropes per side. it took two hours to make everything.
thanks for advices

omg, i suspected there is another way but... holy cow, now i know for next time