A pretty good indicator is your vram. If the 20 frames — was 80 megs then half size, and frames would be half the vram.
As far as cutting stuff up goes.... its still cumulative, and may even use more if the images aren't pow^2
Obviously less frames will give you the best optimization.
Dynamic stuff as Arima said will allow you to use just one frame. Bones, and the sine behavior are a good place to start.