The faf client already allows you to run normal AI games through it so that shouldn't be a problem. I'd say there is more benefits to getting it than not, especially if you wanna run the game with mods or new maps.
Oh rip, didn't see that it's not that you don't want it but rather are unable to get it running. But yes it should be possible to get the faf balance running without the client. Anyway if you have faf installed already you can just run the game with the exe and it should have the faf balance applied without the need to go through the client.
Also I forgot that client doesn't come with the game files so here is the mirror:
https://forum.faforever.com/topic/3151/mirrors-for-slow-downloads