1.79GB for 3 seconds does not sound right, but try it with longer sections of video and see if it goes up much. Those might be one-time things.

What's this you're doing with vegas? Importing? Do you mean capturing from the camera?

Ignore the 60i/60p or 50i/50p selectors. Basically they're for when you want to use Raylight to edit 60i or 50i footage. Has nothing to do with 24p editing.

If you want to edit Raylight in Vegas, follow these instructions for setting up a project:
http://www.dvfilm.com/raylight/raylightTutorial3.htm
Remember your footage is 1080P so only pay attention to those directions... "For 1080P projects..."

Capturing yes sry!

The new raylight (2.0) will let you keep the native frame size of
1440 x 1080 if you use the 50Hz system. Also you can make self-contained AVIs if you do not need the features of Raylight Red (the lo-res
proxy mode).

SO for example if your source material is 1440 x 1080 HDV, you would configure Raylight for

*50 Hz system
*native frame size
*self-contained AVI

By the way the 60Hz/50Hz system setting is different from, and
entirely independent of the frame rate.