Brenden, I had myself considered this path to use such a Sbig camera for dual purpose DSO and Planet imaging. The Inspiration was this chap Ed Grafton who really did some great things with the Sbig cameras.
http://www.egrafton.com Look at this website and check out Ed's guide. There use to be a SBig application called Planet Master, which is now built into the Sbig CCDOps application.
Whiel Ed did take some wonderfull shots there are some limiatations of this technolgy when compared to modern high frame rate UBS 2.0 and Firewire camera's. Even at shorter exposures you will still not capture as many frames as with a Webcam. This is due to the time to download the frame to your PC. Not sure on the St402ME download speeds on short exposure frames. This is an issue with planets like Jupiter which rotates quickly. However with Planets like Saturn and others with a slower rotation this is not such a big issue as you can take the frames over a longer period of time. Hence you will not Ed's Saturn Images are not to disimilar to the best that is being taken these days.
Regards
Fahim