Setting 1: Perfects/Sicks give 100% if Marvelous timing is active?
pretty self explanatory, sick notes could give close to 100% but not exactly (90% i guess)
Setting 2: Accuracy type
Option 1: Combo based
Combo breaks are 0%. Everything else is 100%. This is dumb but FNF players tend to be too casual to care.
Option 2: Judgement based
Basically the current system.
Option 3: WIFE3 Complex
shoutouts to 白音 / siron l ma o

I don't know how this curve works. What I do know is there is a hidden judgement window for 100%, which is 1/9 of the Perfect/Sick window.
Kade Engine has had this exact system (afaik?) for a while, but it's been completely broken since 1.5.4 and no one other than siron uses it anyway.
Also there's the complex accuracy grade system which goes like this:
- F - Fail
- D - Under 60%
- C - 60%
- B - 70%
- A - 80%
- A. - 85%
- A: - 90%
- AA - 93%
- AA. - 96.5%
- AA: - 99%
- AAA - 99.7%
- AAA. - 99.8%
- AAA: - 99.9%
- AAAA - 99.955%
- AAAA. - 99.97%
- AAAA: - 99.98%
- AAAAA - 99.9935%
You might want to add more decimal digits if this setting is on.