Hi John,
you can tell SharpCap to test additional gain values during the analysis, but there isn't a way to tell it to skip gain values or ignore ones. It also expects the gain values to be in order from least bright to brightest, so I think the best thing to do is to cut it out in the driver if possible. You will need to tweak the 'Gains' property which returns the list of gains available and also the getter/setter for 'Gain' as the current code probably has special handling for a value of zero to set auto gain, which will need to be removed so that the real gains are numbered starting from zero.
cheers,
Robin