normal to need clutch adj after a few months on new one?

1 inch is factory spec. for a DD.
You can run as much or as little as you like; between the pedal on the floor and grinding into reverse would be too much; and zero freeplay with the TOB on the fingers would be not enough. One inch is a good starting point. Depending on your starter gear and driving style, you may have to adjust it once or twice in the first summer. The following summer, you can set the freeplay a lil shorter.
Like Toolman says; zero burns out the bearing, so don't go there; otherwise anything goes, but the more you have, the more often you will likely want to adjust it. Just make sure you keep it off the fingers; it ain't like setting the float level where a millimeter is as good as a mile.