I just figured it out today.
If you Google pm 3.02 cbliss, you should find a reddit page. In there someone put a template with all the files you need. I believe they got the most upvotes. They are:
the codeset .gct
info > portrite > (BP) for each added slot
menu > common > char_bust_tex > (results portraits) for each added slot
inside common5.PAC you will need to right-click import texture in each character's CSP for each slot you plan to have and I went ahead and named them according to the pattern.
Stock icons
So how do you add the slots? You put the .gct with CBliss and click "Add to GCT" in the app. Then what you should do the first try is uncheck all the characters but one and add just one more slot to test if you have the method down. You will need to take note of the amount of slots you already have.
From there you add the CSP into common5, the result portraits into menu > common, and the BPs into info > portrite. The stocks in PM seem to be accounted for, but you may want to check that in common5 to see if you have to add some. With all of these things filled in, you can finally add in the .PAC and .PCS (BOTH) into pf > fighter.
I think that's it. I wanted to write this out mostly because there wasn't easily accessible knowledge on it when I had to find out.