What advice I give you?? It's all about testing, testing and testing you need to find the find the best combination for your actually offer and the traffic source.
If I should give you any advice on this, I would suggest you test 4-5 different networks and if all networks fail in your opinion, you should check other types of traffic or find another offer.or of course another GEO, carrier, device to target. The key word here is optimizing!
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