When I got my 35 Azur, I tried the 35 Mono and 40 Mono as well, but the SA asked me if she could be frank with me. She said the 40 looked odd on me, and the 35 was perfect in Azur. I'm 5'3'' and about 120lbs. I would love the 40 but it just looks silly on me! I have seen other petite girls with vintage 40s and it just looks so chic! A matter of personal opinion.
Also, even the 35 can get very heavy if I fill it...I can only imagine how a 40 would be! I might someday get one in vintage, as I love the look on others.