Within Bridge you can click the "Include LTV" checkbox to have FaceBook attempt to use the weighted value of your highest value customer to build an active look a like audience. This new look a like audience will be based on your highest value customers demographics and characteristics.
Note: Look-a-like audience require matching over 1000+ records to be built. It is recommended that in order to use this feature you upload at least 1500 records into your audience. Also, it can take up to 24 hours before Facebook can create your Lookalike Audience based on the parameters you set. Then it refreshes automatically every 3 to 7 days as long as you’re actively targeting ads with it.