You are MOST welcome!
RO uses lots of different leathers for his jackets - including Kangaroo!
As for recommendations - are you looking for the same style jacket? I have found that the RO style/cut that suits my figure best is the Princess cut - here's the style:
http://www.myhabit.com/#page=d&dept...x=46&discovery=search&ref=qd_designer_sr_1_46
If classic is your cut, I would stick with size 40, a thinner leather will just be a tad looser in the arms and chest area. Look for lamb (agneau) or calf (vitello), for the most part, they will be thinner - BUT - there are ALWAYS exceptions with RO leather. It IS confusing.
Everyone has their favorite leather. My preference for leather is LV, calf leather (vitello). It's lightweight. Remember, every season there's something a bit different, the color, the way the leather is treated AND sometimes fit. Again, not consistent. BUT, if it's a bit of an aggravation, it's worth it for the beautiful leather!
This is just my opinion, but I think that blistered leathers have the nicest drape. It's the perfect ratio of leather weight to drape. Blistered leather will look VERY different than your pig leather AND it will also depend on the blistered leather itself. Every blistered jacket is different.
Good luck - it becomes a bit of an addiction!