Stuart you don't need a special kit. Simply take the wheel off and re-insert the spindle. Get a steel pin held horizontal in your new vice and put the spindle over the steel pin (If you want one pop into mine next time you passing I have hundreds of them for marking out building foundations). Slowly rotate the wheel making sure the spindle stays still. Allow the wheel to come to rest, the rim at 6 o'clock is the heaviest part, mark with felt pen. Raise the mark to 3 o'clock and let go if it settles in the same place stick a small balancing weight at 12 o'clock and start over. You will soon have it balanced.
I would be very wary of putting anything inside my tyre other than air. My mate once got a huge speed wobble when we were travelling to Morocco, it re-occurred every time he went over 100 MPH. We went to a little back alley garage who checked it for damage and found the wheel and tyre intact. We got the tyre off the rim and found it to have green liquid inside it, my mate had got a slime like product to prevent punctures put in it at Thunder in the Glen as he knew we were going on tour the following week. The wee mechanic washed it all out and the bike was perfect.
Just my thoughts Big Man
JimmyMac
