An inch of wire isn't going to make much difference regardless of what you use. Good, high purity copper wire is hard to find in solid core, but perhaps DIY Cable has some Vampire wire that would work. You might have better luck with silver wire. Use teflon insulated. If you didn't want to use silver, try a plenum coated cat5, which is essentially teflon. On cheap wire, the dielectric is as important as the wire itself.
If you want to go all out... cryo treat it. This will make a difference.