throttle cable replacement

[Dezza]

I posted this in the Workshop section yesterday and haven't had a response but I need to replace the throttle cable and cruise control cable for the EA. On both, the heat shielding is all cracked and worn. I checked out Ford and they want about $65 for the throttle cable and $130 for the cruise cable, so I checked out the wreckers who want about $15 for each (a bit more in my price range). Do anybody have any tips as to getting good ones etc. Also, how should I go about replacing them, eg. how to disconnect the old ones and get the new ones in, without stuffing up the tension.