>If you're interested in diving deep into this, I would be happy to help and could point you towards some good resources for learning though.

I'll bite. I'm very interested.

>All serious media-buyers (people who run ads) use third party tracking software.

Out of interest, what services are worth looking into, please?

I have a client who swears by Hyros (though I suspect she's being sold snake oil by her business partner slash agency manager, who takes a fat commission off her monthly Hyros subscription spend).