Just wanted to say "thanks" for all of your responses. Her original ring was in the family in the past, and had I not been broke and 21 yrs at the time, I would have had a nicer (and larger diamond) set in it. I'm not going crazy with size, but just putting in a very high quality 3/4 ct. ... doesn't sound like much, I know, but this is about 3X bigger than before (and as much as the ring can handle w/o complete redesign).
Assuming I'm not "busted" (i.e. she figures out the ring is missing and asks) I'll give it to her on the 15th... and post one more time to let you know how she liked it.