As is 500 persuasion is still required to get to the 75 check, but If it's still too difficult I might lower the requirements or come up with an alternate check <3
I don't have exact math, but in my experience characters whose persuasion is high enough at that point (without actively working at it) have generally started with 75 manipulation to begin with? Even something like 475 would be much more achievable, especially with some of the NG+ bonuses 😭
