This is just a general rule of thumb! Before you use any preservative you should first learn all you can about it.
You need to know things like how hot your mixture can be when you add your preservative. They aren't all the same.
You also need to learn how much of each preservative you should use. Again they aren't all alike.
I just thought you might like an "at a glance" kinda chart. This is something I copied some time back that Lab Rat posted:
If your formula contains only oils, butters and waxes and does not contain water but there is a possibility that the consumer could introduce water into the product, you can use:
Euxyl PE 9010
Uniphen P-23
Phenonip
LiquaPar PE
LiquaPar Optima
LiquaPar Oil
Optiphen
Whether or not any of these would be ideal for you; only you will know that.