From my experience you get the biggest gain by using pure silver on the RDA's positive post. The Vindicator already have a pretty decent copper contact area with the negative end of the battery, if silver is just 5~8% more conductive than copper your could take the current contact area of the vindicator's switch, reduce it by 8% and still is bigger than the purges' with solid silver contact
Also, having both (and bunch of rounhouses & rubys), hit wise, i prefer the old switch to the CC, I know there is no arching, but the old style is just one big, single chunk of copper with less moving parts that i *feel* hits faster