This is for the guys...
My friend recently voiced his concern re: giving the perfect ring. He knows what his gal has a certain style in mind, but has something a little different. He's worried about the outcome and as such is delaying the whole engagement process.
I may make some of my female friends angry with this wisdom, but seriously --- it doesn't matter. Speaking from experience I saw there was a ring in the box (wanted to be sure I was on the same page), closed it quick and said yes.
My shared wisdom is this... There are so many wonderful things going on with an engagement- the ring plays second fiddle to all the excitement. Don't worry too much about the exact details guys!!