We suggest it is best practice to avoid targeting the same audience with different ad sets. Here is an explanation as to why this is not a good idea.
Each ad set should target a different audience to get the best results.
Every ad set needs a minimum amount of events in order to begin to optimize. If you create two identical audiences (containing the same people) but target them with two separate ad sets, you are essentially setting up two ad sets to compete agains each other for opportunities to reach the same people.
This can result in both ad sets getting less opportunities to be shown, which will prevent them from optimising. Additionally it increases the risk of overexposing your target audience to too many ads and providing a bad user experience for your potential customers.
For your Top of Funnel campaign we suggest creating one Lookalike Audience and one Interest-based audience. Here is how to do it.