3mm vs 3.5mm Shared Prong

[Cobblestone]

Thoughts on 3mm vs 3.5mm on a shared prong wedding band to go with a 1.5ct solitaire on a 4.5 finger? Any photos of similar combos?

 

[Dancing Fire]

Here is my wife's 5 stone 1.27 ctw. share prong ring from WF..
size 4.75 4mm wide shank all the way around. The solitaire is 1.15 ct = 6.80mm in diameter. A well cut 1.5ct is approx 7.35mm in diameter.

 

[unsettled]

I think my 7 stone is 3mm? And I have a 1.5 carat round. I’m a size 7.5