Thanks Mike,
I used your file size, render best, and the zoom and pan worked well.
By chance a couple of the photos had been cropped or rotated to Vertical, this meant I had to select 4:3 aspect ratio which limited zoom or pan options.
From this I suspect it is not wise to crop in Photoshop first, probably best to use the Pan Crop tool in Vegas.
When resizing I only altered the Pixel size, I did not alter the long and short side to inches, will play about some more.
Thanks again Eric