Conversion tracking pixel place at confirmation page or thank you page?

I am using clickervolt, I wish to track the traffic and conversion on my website

I practice double opt in, hence for conversion pixel I should place at confirmation page or thank you page?

Here my site structure:

landing page->opt in page->email confirmation page->thank you page

My understanding:

if I want to track the traffic that as long as is opt in, I can place at confirmation page,

if I wish to track the traffic fully opt in, I need to place at thank you page.

Correct me if I am wrong.