I don't think Antmf uses custom client.
Antmf you should really give it a try. Not only they allow you to zoom out/in minimap, resize it but it have many other cool options!
There are 2 custom clients:
by Latikai(using it myself):
viewtopic.php?f=11&t=7681and by Ender:
viewtopic.php?f=11&t=50You might have to do this though(not sure if its still needed or not):
viewtopic.php?f=10&t=8388and add those to your exceptions:
http://DonnEssime.github.iohttp://enderwiggin.github.iofirst is for latikai client and second for ender client.