Does the mods you are editing already have a modified Instant Battle menu? If not, you can just use mine. But note if you have to edit the meme file, there's two nodes you have to change. I don't recall now where the other node is. But if you need a reference point, you can open my modifed meme file in the meme editor and find the second instance which will show you where to find it in the meme file you are editing for the mod.
I never tested this method with BFV, so no guarantee that it will work for BFV.
Currently my latest release of BF242 Redux mod now has this feature. So if you want to try out 255 bot madness, you can download that mod from the download section of the forum. It will be the BF242 Redux mod. NOT the older original mod as that one is now outdated.
Also the create game page in the mulitplayer menu is a seperate meme file and my files I provided here do not provide that one. There's a integre value in a certain node that you can change to allow more then 64 players but a EXE hack is needed as the client exe can't host games with more then 64 players. Only Instant Battle singleplayer can do this. You are better off just getting the hacked dedicated server exe that allows more players, then using that to host your multiplayer games for the higher player counts.