have a look on wwwaxesrus.co.uk
they sell highly insulated wire and other single core wire which are for connecting pots etc
it's not expensive, so if you have any concerns about what wire to use then you could just get the highly isulated stuff.
sorry, i know that doesn't actually answer your question but i find, as long as it works (insulated or not) then just use it.
the last pots i hooked up, i used some spare wire that i stole off the arial for my stereo, it works just fine and it's not highly insulated or anything.