Well, I get more than 329 meters!

Seriously though, did a 200km round trip last weekend. Snow and ice on the road, temperatures between -7 and -11 and speed mostly between 80 and 100 kph, used heat in the seats for 3 seats and heated stearing wheel, normal driving mode and climate set to 24. Used 52%, so would estimate a usable range of about 375km.
Edit: I have the dual motor, with WLTP of 485km
A Norwegian motor publication does a range test with 20-30 cars two times a year, one in winter and one in the summer. The MGS6 actually lost the least amount of range compared to it's WLTP range. On the day of the test it was really cold, -15 to -30, and the route goes from Oslo and towards Trondheim, and it's mostly uphill for the first 350-400km. The MGS6 did 345km in those conditions, but they drive until the car stops and is completly drained. MGS6 drove further than Volvo EX90, which has a WLTP of well over 600km.
Unless you are driving long trips regularly, range is not that important imo. As a rule of thumb when going on longer trips, charge when you can, not when you have to.
Here's a link to a summary of the test
Bitende vinterkulde gjør elbilenes kapasitet mindre forutsigbar. Slik var de siste kilometrene for de 25 bilene i vinterens krevende rekkeviddetest.
www.motor.no