Possible to change indent length from 8 to 4 spaces in mg?

[Martin Gignac]

Hi,

I've been trying to figure out how to change the indent length when 
pressing the TAB key in mg from the standard 8 spaces to 4, but I haven't 
been able to find any setting that would seem to achieve this.

The man page and Google didn't turn up anything.

Is this at all possible in mg?

Thanks,
-Martin