Selle Italia: Lady Gel Flow vs Diva Gel Flow

[Owlie]

The inner thigh chafing might be a sign that the saddle is too "pear"-shaped (ie, the transition between the nose and the rest of the saddle is too gradual) for your particular anatomy. I mention this because I have the same problem with the SI Lady Gel Flow.

7mm may not seem like a lot, but it can make a big difference. Have you measured your sitbones to make sure that the 153mm is in fact somewhat wider than your sitbones? If you haven't, there are several threads on here telling you how to do it (so you don't have to go to the LBS and sit on the buttometer!).
The other reason for measuring your sitbones with the Diva is the really big cutout--some have a tendency to sink into the cutout, resulting in more pain. (They'll tell you about that once they chime in!) So make sure your sitbones are wider than the width of that cutout. I'm not saying that it won't work, it's just something to be aware of. (This is actually my reason for staying away from the Diva.)

I get the impression that the feel of the saddle otherwise is not all that different from the Lady Gel Flow, though since I haven't tried it, I'll let others comment on it.

Hopefully this helps!