Question

I would like to clarify having  800 dollars  per adset for lookalike  2 adset , however conducting ab test for lookalike audience is 400 dollar  so main point is  setting up the lookalike adset and ab test , should i just first place the 800 dollars in each adset first  after that  duplicate the adset for ab test and pause the previous adset and change to 400 dollars and place 400 dollar for the new adset for ab test audience as mention.

Answer 1

If your goal is to A/B test two Lookalike audiences, don’t launch the $800 ad sets first. Instead, set up a clean A/B test with two ad sets at $400 each, so you can directly compare performance under the same conditions. 

If you've already run the $800 ad sets, pause them, duplicate for testing, reduce the budget to $400 each, and run your test from there. 

Keep all other variables (creative, placement, etc.) the same to get accurate results.