I don't *think* anyone has mentioned this, but if I'm repeating somebody else - my apologies....
I'm not a fan of center stones with angled corners set with stones with square corners. They're two different cuts - and say 'different periods' to me. If it's your thing - great! - have at it! but for me - no.
Yes, your mother's diamond looks whiter, yes, the five stone would be (way) too wide for my aesthetic (and I understand you've already made your own decisions re that - but just staying on topic re the original post), and agree that Leon's side stone contribution isn't cutting the mustard.
I think all the bells and whistles are detracting from your gorgeous diamond - and I'm someone who likes a BIG look. Were it me, I'd rotate the sides so they're horizontal rather than vertical, and go with tapered bullets. I love that look (if this interests you at all, have a look at my thread from last year called Boadicea the Valiant) and think it would look killer with your stone and the proportions you have, which are inflexible (your finger and your main stone).
I really appreciate your candor — that kind of frankness is what keeps me coming back to PS! Totally agree on all points re the five stone design and I’m glad we 86’d it in short order.
I toyed with the idea of setting the baguettes horizontally (hey, if it’s good enough for Grace Kelly and mrs-b...), but my boyfriend vetoed the notion on sight. He likes what he likes and really doesn’t like what he doesn’t — I don’t pretend to understand the whys and wherefores, haha. But I agree it would look lovely!