Great! Then you don't need to do anything in Color Settings. Leave that window alone.
Now that you've saved the ICC file in the library, just soft-proof as normal: https://www.damiensymonds.net/2010/03/bit-about-soft-proofing.html
Yes, I know.
Earlier in the thread you said that they don't require you to convert your files - you can send them in sRGB as normal. Is that still the case?
Sometimes I find I have to take the scale down really small - like 20% or something - so I can get the gradient centred exactly where I want it. Then take the scale back up again.