Errr simple question, you are saving the changes you want under 'custom' aren't you? and for changes on our server you need to be on the server not someone elses. The 50 mile tank thing is a new one for me, never seen it, we have someone who'll be able to help, and although your post is long some of it doesn't make sense. To get custom levels you have to earn them, if you ain't got them you are stuck with stock weapons .
So come on our server join a game, then come out and select the part to change weapons, select say custom 1, get what you want, go back to game and check they're there. Come off the server, rejoin, select custom 1 and see what happens. i.e. do the simple things first before anything else, let us know