The GCF is 10w.
The GCF of 30w and 75w is 15w.
30 W
Venezuela
No idea
30w, 10-30w or 10-40w
The coordinates of that point are 14N/70W . The point itself is located in the Caribbean Sea, about 98 miles north of Aruba.
Punta Arenas
5w-30w 10w-30w in areas like Phoenix, AZ
maine
Chile and Santiago are the closest.
I would not recommend it, stick with the straight 30W.