Do whatever looks best resolution wise. If you record at anything smaller than 640x480, definitely use 256x224 and keep it that size and ratio (unless you stretch it out to something much bigger, like 640x480). If you record at bigger sizes, especially using filters, then you can go ahead and stretch it to a 4:3 aspect ratio and use something like 640x480. Basically, test it out a bit and see what works well.
The video's framerate can be anything between 15 and 60fps, as long as there isn't any frameskipping or lag being recorded. Even 15 fps will look smooth enough, as long as it's a consistent 15 fps, so go for consistency. In other words, just pay attention to the actual perceived smoothness, not the numbers, since they can be misleading when the framerate varies.