Netting Floor for shelter. Any drawbacks??

As I said before, we've used a homemade footprint below the netting of the Hexamid. We do this when the ground is muddy or recently grazed by sheep and goats (don't want that mess getting in the netting). We use it in addition to the groundsheet inside. It is cut smaller than the groundsheet and any water on the netting reaches the ground before the footprint.
We've had no problem with it, and it has always kept the bottom section of netting dry. Of course, if you ended up with water running under the shelter, the netting would then get wet, but that comes down to site selection, and anyway, you'd be no worse off than without the footprint.
The downside is that you're adding weight.

You are right, if you sew the netting to the top of GC, the water may run into GC and collect there.

But what I thought is to sew netting still to the top, but leave some extra height of the netting for two purposes:
0) to solve the problem you've mentioned. When the netting height is double than actual needed, it will sag in the middle. So all the water will drop into ground. I do also considering the modification you've talked about – to sew the netting not to the edge. However this may make it necessary to seal that additional seam, which will result in added weight.
1) If I wish to setup the tent not pitched to ground but at some height (for better ventilation for example), the sewn in netting seems a constraining factor. So having a little extra does make sense.

What is interesting is how all these modification will affect total weight of the tent.

Greg.

This thread is on point for me. I almost pulled the trigger on a cuben pyramid with a sewn-in netting floor. I was convinced by others in that thread that a cuben (or silynylon) floor sewn into a netting perimeter made more sense. It is a more costly alternative especially if I go cuben with the flooring too. In the end, it made more sense for my needs but YMMV.

We each have our specific wants and can-not-haves. I do like the idea of the netting sewn in an inch or two from the edge. It would create an awning effect and help to shed water from the netting area.

What about making the netting + sewn in GC removable from the tarp? Maybe some Velcro may help to attach it?