Argonath
Chieftain
Argonath: I added the extra space at the top of the America map and the took a screen shot of what it would look like if I joined the two halves as they are now. As you can see, we need to add some ocean in between the halves. You will need room to complete the landmasses for Newfoundland and for western North Africa. How much ocean do you think you want in between? Total, counting the space for the additional landmass. I can't add more ocean after I join the halves because it's too much of a pain then. Also it has to be in multiples of 10 or the grep work becomes too much of a pain.
I'm no too sure. I'm looking at a map right now, and the size of the Atlantic is about the distance from Ukraine to Spain I think. So, whatever the width of the Europe map is, use about to thirds of it- probably around 100 tiles or so. You're guess is about as good as mine on this one. If you do make it 100 tiles we're looking at a map of biblical proportions here, probably the one of the biggest ever on civ. So maybe just use enough to require astronomy to get to America, like 10 tiles between em? I'm not sure and I'll leave it to your judgement, but definitely make it take a couple turns for a galleon to get from Europe to North America for sure.