Flick-off's point about the S1C is valid but mainly because the wing span is shorter (one bay) and therefore the MAUW is 100lbs less than the S1D/S1S.
Average male pilot and much fuel just wouldn't be legal in the C model.
The S1C only has ailerons on the lower wings.
The S1D/E has 4 ailerons, larger wings but they are M6 airfoil - ie the "flat bottomed" wings.
The S1S has symetrical wings - in reality they are not perfectly symetrical as top and lower sections have slightly diffeerent profiles.
All 'S' models are injected and some 'D' models, too. I would recommend that you avoid normally aspirated Pitts Specials.
Legal Approach - your old aeroplane is the one that I most recently know of as being at Langham. I know it has subsequently been sold on. Perhaps Flick-off would know where it is currently based? (Good luck in the Icicle today - FO!)
Italy. Must have been quite a trip! I would love to take mine to Portugal and probably will - can you imagine a Balbo of Pitts' migrating south for a summmer break?
Going to go fly mine now.
Stik