I would like to know which metric I should be using to report correctly on CTA across my website.
Currently i'm using "Instances".
That is correct. There is more information on the differences between props and evars here: https://marketing.adobe.com/resources/help/en_US/sc/implement/props_vs_eVars.html. Let me know if you have any additional questions.
Thanks for the reply.
My CTA click report is tracked using prop (non-persistent variable) which doesn't allow me to use Success events as a metric. Is the reasoning correct? If not, could you explain me why I cant use my success event (checkout) as the metric?
You can use use any of the success events to report correctly on CTA.
Please see the following link for more info :
Thanks & Regards