So before you embark on more of the same, see where the last attempt lead to:

Those who ignore history are bound to repeat it : http://forum.keypublishing.com/showthread.php?117256-Restoration-enquiry

And 2007’s attempt
http://forum.keypublishing.com/showthread.php?67068-Difference-between-Restoration-Repro-Replica

And 2005’s attempt
http://forum.keypublishing.com/showthread.php?46247-Originality-of-restored-aircraft&p=715050#post715050

It’s very difficult to come up with definitions that really fit. My primary experience is with my family’s restoration of a steam wagon – it was restored from a chassis, so there was only, say, 25% original material remaining. However, original spares were used for around another, say, 45%, so it’s in a sense a composite restoration, but with a very clear original identity. So we have something with 70% original parts, but it could definitely be considered “multiple source”. Does that make it Cat 7?

It also strikes me that AR213 is WAY too far down the original list. I’d suggest it’s likely much more original than AB910 (AB had a rebuild after the collision with the Harvard, whereas AR’s only “complete restoration” was done with great care to maintain originality).

My own opinion is somewhat nuanced – and it’s a multi-dimensional issue. Below are the criteria that I personally think are important (in no particular order).

Criterion 1. The range of authenticity – from “full avionics fit and luggage compartment” to “stock WW2 equipment with weapons”.

Criterion 2. The range of originality of the original airframe – from “completely original, conserved airframe” (e.g. “Spirit of St Louis”) to “Restored original airframe” (e.g. Alcock and Brown’s Vimy), to “heavily restored original” (e.g. Hurricane R4118), to “restoration incorporating original components” (e.g. Mosquito KA114), to “data plate restoration incorporating token components” (e.g. Spitfire EE606).

Criterion 3. The amount of original structure, much as above, but not considering the origin of the components for composite airframes. An extreme example here would be that the CAC-18 (Aussie Mustangs) that have ‘adopted’ identities of P51D’s for certification reasons. They might be 0% original on criterion 2, but 100% original on criterion 3. Other less extreme examples would be aircraft like TA122 at Salisbury Hall, where the fuselage is the original component, but the wing is from an entirely different aircraft.