The Mainstream Vertical Test
This is the same plugin called Gallery with Thumbnails but as a Veritical slide:
Width of pages set to 1100px wide.
1) 3 nav options: click and drag your mouse over the image and scroll to next page auotmatically plus nav arrows, plus thumbnails
2) Nice and big we can read
3) Responsive to the size of screen
Cons (but can be fixed)
1) This particular plugin i found doesn't have auto move to the top after you click the thumbnails. But we can probably custom code that if need be.
2) Double page spreads - we can show the 2 page as one image then split, or just show the 2-page (we just need to add custom code to align the image to the top of the window, Rogerio should be able to do that easy)