Hi Dali,
What Nordorst and what VDH are u contemplating? To my mind the cables are very different sounding. Vdh seem to roll off treble and as such are laid back which can make u feel a loss of detail and some Nord can sound brittle and thin in some set ups. Please try all the cables before u buy. Try a few kimbers,vdh,supra,Transparent(if the budget permits), Nordorst and take a call.
Ur dali must have come with tiny rubber feet? Hope u have used them as they isolate the speaker from the stand.
Blue Tack can be used without a worry as its an inert material and does not soil.
The top plate is supposed to be smaller than the speaker footprint so thats not a problem too.
Am sitting with quite a few cables and have tried many in the last decades but i still cant pin point the one for ur set up or your ears!!!!
Rgds