I am having the exact same issue bro, except mine is hosted and I'm on a deadline(probably shouldn't have bought hosting till I fixed all the damn problems) ;(
But this issue is strictly by creating a patch via client editing. Now I have no idea how to do this, I'm just a DBA and SQL dev so I made a thread asking the EXACT same thing, on how to do it. Hopefully somebody can tell us where patchs are located in Legion, because I know that WotLK 3.3.5a could be client edited to fix the that problem, and not only that but FireStorm world of Warcraft has fixed the problem themselves by introducing a custom patch into there client, and that was done on there client(7.3.5 trinitycore).
I know it's possible, cause Firestorm did it. Now they're an absolutely huge server but I'm willing to do whatever it takes to be able to fix the problem as well, as it's a key aspect of any WoW server.