which jumpers for Vandersteen 2 Ce's??

Biwiring on Vandersteen's makes a really big difference. Instead of buying jumpers, I would go buy a spool of decent, low cost speaker cables. Something like Monster or entry level Audioquest. It will sound much better than jumping the binding posts.

I agree with Zd542 or go to Radio Shack and buy their 16 gauge speaker wire.

Yes on the above recs.

For me, I found the Radio Shack 18 ga is surprisingly good. For some experimenting, you might want to try their 16 ga on the woofer and the 18 on the tweeter.

Also, I'm not sure why but the 18 sounds better than the 12 ga. I have some guesses (like the thinner dielectric) but I don't listen to guesses or theories. Just try it.