GTA V Should I mod disk 1 or disk 2?

Hi guys, looking forward iso modding GTA V. Quick question though. Which disk am I supposed edit? Disk 1 or disk 2?

I was under the impression that we are to install the original disk 1 and instead mod disk 2 (common.rpf) and play from that disk. But I've read a couple conflicting posts elsewhere.

Thank you for your help in advance!

 

Disc 2, disc one is full of containers that install to your HDD.

 

Thank you sooooo much!