Tristan, I've been on my "sick bed" for the last week, so I'm sorry if my response hasn't been as quick as you would have wished. Also, if you want others to reply, please don't ask one person (in this case me) for the reply, as others tend to stand back.
I'm away for the next few days on 'Christmas Duties' but as soon as I'm able I shall answer your queries.
Disc sizes don't surprise me
The Stradale is probably small than the Group 4.
In passing though I shall say 'why not synthetic?'. As long as it gives you the right XXwXX numbers and wear performance I see no reason why it shouldn't be used, especially in a higher performance engine such as the Abarth. In fact, I think I have synthetic in my Abarth - but I'll check as soon as I can and get back to you.
What was the rattle problem T??