I don't know of any estimation tool or rule. I suspect there are too many variables. I suggest you get the wine as close to freezing as you can -- wine will not freeze at 32 F / 0 C. Keep it there for 2 weeks, then rack. If you're under 40 F, it will still help.
This may not completely reduce the acid, but it should help. My experience with Muscadine is that it needs a bit of back sweetening, so cold stabilization should reduce the amount required to balance the acid.
Note -- I've read numerous recommendations to chill the wine down to the wine's freezing point (ranging from 20 F to 27 F, depending on ABV and other factors). I've also read two research papers that stated that chilling wine below 30 or 32 F does not change the amount of bitartrate precipitated. Based upon this, I see no point in chilling the wine below 32 F, as it doesn't help, and freezing wine damages it.
Unless you're up in the NC mountains, cold stabilizing on your porch (as I did in NY) won't work. If I had to cold stabilize now, I'd put the wine in 4 liter jugs and put in the fridge for 2 weeks at a time.