Doolittle, whilst in broad agreement with your proposals, I have to say that your "catholic" rules regarding Spitfire lettering are a bit over the top, given that these were applied locally by groundcrew to comply with some broad interpretation regarding aircraft identification, (The Air Ministry or Duxford may know what these were).
If you look at the photographs here:
http://www.spitfireperformance.com/spit1vrs109e.html
you will see that you will need to add other squadrons to those of 19 & 22, which had stepped lettering.
Even those squadrons which had even lettering, had aircraft within them with slightly eccentric application, probably due to time constraints or inexperience of the lad that painted them on. I suspect that if it could be clearly read, it got passed as ok.
If you wish to enforce rules then please supply photographs of the aircraft of every squadron that flew Spitfires (and Hurricanes!), and for each month of the battle as it's likely that markings varied over the months, (replacement aircraft being painted by different people as one example). Photos of warbird repaints and pretty profiles will not do if accuracy is your aim.
Yours constructively.