DXF v's IGS file formats / advice needed

Hi all,
I am trying to develope G code for a section of a boat,, the
original design is in Rhino, and the sections will be cut using a 4
axis wire machine
I started using DXF file format but got a million pointsand lots of
confusion on my part.
I then switched to IGES or IGS and now have a nice easy to follow
section ,
I am looking for accuracy of about .5 mm but wonder how much
accuracy , if any ,am I loosing.
Can anyone explain the reason for the different formats , and how
they'll effect the G code generated?
thanks.
Mike