Alan,
I'm interested in following all the A380 aircraft, the British Airways B747 and B777, so I use Fleet Watch to follow these.
For the civil aircraft, I can use airframes.org to look at the airline fleets and see what the aircraft registrations are, for example, see this:
http://www.airframes.org/fleet/bawIf you look at the registrations, you can see that they run in order for that type of aircraft, except for a couple of out of sequence registrations, hence the G-RAES entry.
I know that Emirates, Quantas and Singapore Airlines are operating the A380, so I can use airframes.org in the same way to get those registrations, and again they run in sequence so I can '*' as a wildcard.
The Hex codes in the alerts box are widely known and are posted on the internet, so I've got these to catch most USA and British Military aircraft.
Hope this helps.