Great find RUI and knowing your history on ebay I'd imagine that you got an excellent price.
Robbed some info from another forum that I thought might be useful. The petals you've bought are significantly lighter than the 10 spokes that you were considering. Would you consider fitting the Abarth springs and possibly get a decent pair of shocks to beef up the suspension at a later date ?
16" wheels = 8.4 kg + 8.1kg Pirelli = 16.5 x 4 = 66kg
16" wheels (OZ Alleggerita) = 6.3kg + 8.1kg Pirelli x 4 = 57.6kg
17" wheels (OZ Alleggerita) = 6.5kg + 10kg Pirelli x 4 = 66kg
17" wheels (Esseesse) = 10kg + 10kg x 4 = 80kg
then the 5 spoke petals (3.2kg heavier)
10 spokes (14kg heavier): these are 11.5kg each
P.S. There would be a good market for those Abarth discs & brakes for 1.4 owners - don't give them to the A500 drivers.