You can have GWX for a MP game. Have a second install just for MP. Clean Stock 1.4b + GWX + Dec 23rd Fix, this is what I & other members use. Touch wood, no problems yet.
You are always going to run into the same problem whether you use 1.4b or GWX + Dec fix, unless you pre-arrange a game with members from here or elsewhere you can never guarantee that your files will be the same.
I know it seems a lot of effort to play MP but it is worth it. Keep your eyes open for posts in SubSim stating a start time for a MP game. You can be certain that any game initiated here will only be GWX + Dec 23rd Fix.
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