For optimal of ASO testing, we recommend you test 2-4 icons, 2-4 screenshots for Screen1 (or 2-4 Sets of Screenshots), and possibly a couple of Promo Arts, if your app uses Promo Art.
It is best to test as diverse of creatives as possible between variants so the results will give you an idea of what kind of creatives work best for your app for each element. Once you understand what kind of creatives work best, you can start to narrow your scope and test more creatives of that kind. Testing very similar creatives is inefficient as the performance may be very similar, and it would take a lot more data to determine winners.