Just picked up a pair of Cobra GT3 seats to replace the Procar Scat seats which came with my newly purchased 240Z. What is the easiest way to adapt them to my current bracket?

Nice!  You can do a search on the upper right of the screen and search the term.  Make sure you set it to search 'everywhere' to get the most amount of results.

Here's a link to one I did as an example

https://www.classiczcars.com/search/?q=seat rails&quick=1

 

Enjoy!