Readings off my grapes wash...

[Grappa-Gringo]

So I've picked my grapes several months ago...mashed them up, and added about 18 pounds of dextrose via a hotwater mix...
Pitched my yeast...and watched it go...it did it's thing and now I've got approx 5 gallons of this wash that's measuring the following: 11.8% /vol 1.085 SP.GR 20.4 Brix....

Which calculator should I be using to have some "idea" of what my outcome is going to be?
My wash hasn't gone off...and has a lovely aroma in the fer-mentor...I haven't filtered it either...
I'm running a 5 gallon keg, with a 1 1/2inch column with a traditional liebeg water jacket....
It's a new build for me...I''ve usually used a pressure cooker with a 1/4 inch running out of it...
Any ideas -comments would be great...
cheers