Chris,
The following may answer part of your question:
http://wiki.glidernet.org/opt-in-opt-out states the following:
To clarify:
You can either use your internal (factory) FLARM ID (which is based on the serial number of your FLARM unit) or your ICAO address (if your aircraft has such assigned). In either case enter the ID you use into the OGN Devices Database.
When entering the details on the OGN database you can determine what others can see (ie. just the hex or full tail number)
I've registered our aircraft as:
Device ID Aircraft type Regist. CN
401FF5 RF 5 G-BJXK JXK
I'm not aware of a G-Info type lookup.
Mike