Cable length

What the cables is better to keep shrotest way, speaker or interconnect?
If I make my speaker cables 8'- I need to use interconnect
between preamp and amp around 2m.
If I make my intercoonects under 1m I have to make speaker cables 12'.
My system:
preamp Linn Kairn
amp Golden Tube SE-40
speakers Vandersteen 2CE.
And, by the way, probably somebody has something simular-
what the cable better to use?
Thank you for your help.