I suggest you should rather just put the lines neccesairy for the zooming in a file. I doubt anyone would just overwrite his autoexec.cfg happily. People can then just copy and paste if they want to try this. (you have already offered those settings below anyways)
Also, you should include the keybinds to that file, instead of messing around with the keymap.cfg.

thumbs.db - this is some file from your image browser and has nothing to do with cube.

You should edit this imho, it might lead to confusion/frustration amongst users, especially those not yet experienced in config-stuff.