I have found that the key to maintain quality in video production is ratio. First, you want to determine if you are going to produce in 16:9 or 4:3 ratio. Here’s a list of popular dimensions for each ratio:
Let’s assume that you know the finished video should be 640×360. This is the size you want it in your Lectora title for example. That does not mean you need to record your screen at 640×360, but you do want to record in the same aspect ratio family. Since 640×360 is a 16:9 ratio, you can record your screen at any of the sizes in that ratio.
I’ve had better success resizing the video once it’s in Lectora, but it should scale down nicely and maintain quality.