you certainly arent going to get close to 400A with 3 TZ85A. Heck when I've smoked a TZ85 with a stalled brushless it didnt pop the 80A fuse

10AWG is about 2.5mm2. A Maxi fuse is fine for feathers generally, a mega fuse on your setup will look big.
I run 2 x TZ85 with 50-60 brushless on 80A fuse. its fine. I have popped a 80A fuse with 2 DeWuts but thats another story...