Understable mids are designed to be thrown with less effort, more glide and earlier turn in their flight. There is not ONE line or flight path which a disc will fly when mastered but yet MANY lines and different flight paths from the same mold-- then you have mastered it. Being understable these discs will be the most workable of all discs on the market so when you throw with hyzer they should fly straight and fade left-- you throw them flat and should see pretty straight flight with a slow right turn and not much or no fade-- give anhyzer and they should hold all the way to the ground and mirror the first shot but finish right.
Then mix in the left to right hyzer flips, sky anny stalls, rollers, and a few other shots-- you now officially mastered the US mid.
To address the fuse specifically though if you throw it flat it should fly fairly straight as it has a decent amount of HSS(turn rating) for an understable mid which means it takes a lot of speed in order to actually turn the disc over and get it off the line which it was released but it does not have the LSS (fade rating) of an overstable disc which want to get to the ground faster than an US disc-- they don't go left more.