I am not sure, even with all my games with zed, i am pretty sure it's at your back. I haven't really noticed where the enemy is facing when i ult, it always seems that they are between me and the shadow that R spawns in zed's initial location, Now, in the heat of the moment i don't really notice. What i can advise you is that, whenever he ults you, depending on your champion, know the exact cast time of your cc whatever it is and time it so that after .75 seconds the skillshot will be exactly behind you, to make sure just don't move and prepare your ability, this way he can't dodge it, he couldn't dodge it even with the old ult that had no delay. For refference, watch faker's videos when he picks ahri against zed and see how he uses his charm, in some cases, the footage is pre patch 5.9 when Zed had no delay in his ult swap and he always hit them with the charm. I am pretty sure that he always appears on your far side, like Katarina's shunpo, regardless of where you are facing. Your other option is to wait for him to emerge from untargetability and flash/dash away from him, but NOT opposite of him. If you flash on the opposite direction of where he is, you will end up next to his ult shadow. Dash to the side and actively try to dodge his Q and try to outplay him while you waste his 3 second window for his ult. After that ends, shit on his face