Paul, also if you use the color wheel, check the the guide star after the calibration with the blue filter selected. If it dims considerably or disappears, it is a red star. Sometimes other stars in the field will show brighter than that star with the luminance filter. Click the Auto button. The square will flash around the brightest star in the field. Do this with the blue filter selected. This will also prevent the "Guide star too dim" message during guiding when filters are switched.
I then click the autoguide button and have it autoguide with the blue filter still selected while I check the exposures in the Color tab or Take Image tab and the destination and filename prefix in the Autosave tab. Then I start the light exposures.
Focus of main image and calibration of guide star, Luminance filter.
Final selection of guide star and start autoguiding, Blue filter. Allow it to center the guide star before starting exposures. Allow 15 seconds of delay to recenter the guide star between exposures in the Color or Take Image tab do to the long downloading time, especially if you binned 1x1.
Joe.