Hi!
Make sure to have the Show overlay on mouseover? option enabled on the Theme Options -> Isotopic results panel: http://i.imgur.com/RL35ubh.png
Otherwise I think it won’t work.
The ajax page loader works if the AAPL plugin is installed. It’s a deprecated function, will be most likely removed soon. (too much trouble maintaining it)
I guess the best way to make a smaller loader is to apply a scaling CSS code. Something like:
[html].probox .proloading .asp_loader {
transform: scale(0.5);
}[/html]
This will make it half the original width and height, but leaves it in the center. Sort of zooming it out. You can try higher/lower numbers to find the best fitting size.