The G2V calibration method used is described on the following page:
http://starizona.com/acb/ccd/advtheorycolor.aspx
A G2V star catalog plug-in for TheSky 6 may be found at:
http://www.astrodon.com/Orphan/g2v_database_for_thesky6/
Our results are:
For the RCOS / STL11000M / Goldman I-Series Filters:
Red : Green : Blue = 1.02 : 1.00 : 1.09
Measured on 12/05/2006 using WDS A 2011 8.8 magnitude at altitude 55 degrees
For the FSQ / STL11000M / Goldman I-Series Filters:
Red : Green : Blue = 1.22 : 1.00 : 1.12
Measured on 11/18/2006 using SAO 76031 7.3 magnitude at altitude 68 degrees
For the RCOS / U47 / Goldman E-Series Filters:
Red : Green : Blue = 1.11 : 1.00 : 1.04
Measured on 9/17/2007 using SAO 163948 8.5 magnitude at altitude 75 degrees