Here is the revised CoG part of the loading table attached to make clear how the CoG and use of the bob weight (inertia device) were connected in the case of the original standard elevator:
With DeHavilland propeller:
CoG range 5.4"-7.9" aft of datum point, no inertia device needed
CoG up to 8.2" aft of datum point, 3.5 lbs inertia device
CoG up to 8.6" aft of datum point, 6.5 lbs inertia device
With Rotol propeller:
CoG range 5.4"-7.5" aft of datum point, no inertia device needed
CoG up to 7.8" aft of datum point, 3.5 lbs inertia device
CoG up to 8.2" aft of datum point, 6.5 lbs inertia device
Regarding if the currently flying Spitfires have the bob weighs installed, here is link to a picture of the elevator linkage of the Spitfire Vb BL628 (from spitfiresite.com):
http://spitfiresite.com/2010/07/anat.../07ar_fuse_001
Edit: Attached also the quote from Perkins and Hage to show how the use of bob weigh and CoG at aft center of gravity are connected
