We run slicks as we share the permanant carpet with touring folk and if we use minipins it will rip/fluff up too much.
I get mine from hobbycity.se or evolutionracing.se it better that you contact them yourselves that way you can save a postage cost from them to me.
Inserts: I use AKA red or Proline blue, I have found that tubby foams etc are too soft. I also wrap the thicker double sided tape around the rim to help fill it out, which is needed more for later on in its life as they tire can get soft. ** Dont forget the breathing holes!!
We also use addative then clean them with brake cleaner or lamp oil.
Hope that helps and if you get stuck contacting the shops then let me know. Try hobbycity first and say I (Simon Frost) recommended them to you
