There is a simple trick to adding user fields to the light info record.
If you edit the "Light Info Record" and add a field that matches a field in the lighting device, the lighting device will automatically pull the information from the record as the default.
So if you add "User Field 1" to the light info record the information will automatically appear in the "User Field 1" of the lighting device.
One caution with this you need to update all your light info records with the new fields or you will get the warning "This record exists, do you want to ...." evry time you import a symbol with different record fields.
Also you can customize the user fields of the lighting device, so if you open the plug-in editor and change the alternative name of "User Field 1" to "Voltage" and the "Light info Record" contains a field "Voltage" the information will be transfered.
In earlier versions of Spotlight it looked at mutiple records, but this created major problems when both records contained the same field names, so operating with mutiple records had to be eliminated.