I tried doing it the way you and Devlin show, but there are a few problems. First it doesn't give you an option of how long to display the slides for, I generally have each slide stay up for 30 seconds. Plus when I did it this way it still took 5 to 10 minutes for it to save 10 slides and each slide only stayed up for 4 or 5 seconds.
This is why I now have to create an individual slideshow and get all the settings correct before I export it. I export in display at 1280 x 800 because that is how our projector is set up and with 30 second slides it takes 10 to 20 minutes to export it. Longer if I have more slides.
The thing that is frustrating is that before the update I could choose export, choose quicktime, type in any size (1280 x 800), choose amount of time for each slide (30 seconds) and check yes or no to music and export it and it usually took about 10 to 15 seconds (not minutes) to save it. And it looked great with cross dissolving fades.
I thought the general goal of updating something is to make it faster and more efficient, not slower and more time consuming.
Is there anyway to go back to the iPhoto before the last updates?
Play the slideshow first and while it's playing click on the screen. The settings pane will show where you can set the time, transition, etc. Now this is for slideshows created by selecting an album and using the Play button at the bottom.
I don't think you can export to a QT movie with the size ratio you've posted unless you choose Custom and then Options then then Size in the subsequent export windows.