Thanks Eddie.

For Vera and Eddie:

How much do you overlap the images when shooting ?
Do you shoot in landscape or portrait format ? 

Looks like I would need about 6 shots wide in portrait to get 3:1 ratio so I would imagine shoot  about 10 shots to get an overlap of 30% .

And every one said, 'If we only live,
We too will go to sea in a Sieve,---
To the hills of the Chankly Bore!'
Far and few, far and few, Are the lands where the Jumblies live;
Their heads are green, and their hands are blue, And they went to sea in a Sieve.

Edward Lear
http://www.nonsenselit.org/Lear/ns/jumblies.html