Hi Rosea,
the best solution is not to encode to any format, just leave the clips as a "set". You can do this either by File -> Close/Save all Clips, or when exiting the application (LiVES will prompt you for a set name).
When you save the set there is a checkbox "auto load this set when LiVES is started". If you check this, then the next time you start LiVES it will ask you if you want to reload the set.
You can have any number of sets on the disk, so any time you can just load the one you want to use. (File -> Load set). You have to close the current set before you load a different one though.
You can also start up LiVES with any set, by using: lives -set <name_of_set>
Hope this answers your question. Good luck !
Salsaman.