I am thinking of getting a Helix 7 G2 and a ZL card for AutoChart Live mapping. Since the Helix 7 has only one card slot I am assuming it would not be possible to overlay the AutoChart Live data on top of a mapping card like Navionics. But what about overlaying it over the built-in basic UniMap that comes with the Helix 7 unit? I am assuming the UniMap has a bit more detail than the ZL map.