I’m glad you were able to almost get there.
As for the missing piece I did find this discussion mentioning that it seems to be happening for some users, but not others and things they have tried. If you are able to right-click and copy the User Parameters and they are there as the original poster of the discussion mentioned, it most likely isn’t an issue with PostLoad as you said, but I’ll double check with my colleagues to see what they think.
You could check out one user’s example project from that discussion to see if their user params show up in the bp for you since it didn’t show up for some users.
Please let me know if the discussion resolves anything for you, thank you!