Hah, problem solved! "Castrator", written by the author of AS!2, took a 3.2GB file down to 105MB. Brilliant!!!!
http://www.astrokraai.nl/castrator.php
I can now capture routinely in 1280" resolution and not worry about the mammoth file size (lossless AVI), which will make it much easier to keep the planet within the chip's FOV!