Momotaro on FB told be that the 702 is able to stretch out to 0.75 inch.
Regarding that the tag32 which is measured as a W33 will evolve between W32.5 and W33.75. Since I am a 33 I just thought it would be ok.
Now concerning the JB0101 it is supposed to have the same cut as the JB0102 that I tried today in tag31 and tag33. The tag31 was way to small and the 33 way to loose. I just assumed the tag32 would be perfect.
To my eyes it makes sense but of course I could be completely wrong and I won't be ashamed to admit it here when I will receive them !
Regarding the tight measurement, this is not really an issue for me since I really have thin thight. The worst thing that could happen is that it would be a bit too loose around them. My main pb in jeans sizing has always been the waist.
Anyway, I would really highlight the fact that I really appreciate your help and advices and I really take them into account among all the information I gathered on the web