PostProcessAAQuality higher than 6?

I know I can easily change between presets with r.PostProcessAAQuality, but is there a way to configure this presets? I need better AA quality than the default preset num 6. Using FXAA by the way.
Thank you!

Hello Musemeghini,
It might be a bit late since it says here that you posted this question in 2017, BUT im going to try and be helpfull none the less.

There are these Two nodes called “Set Anti Aliasing Quality” and “Get Anti Aliasing Quality”

This might help you with what you want to do, if you didnt give up or figure it out yourself ofcourse!

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