There have been so many great suggestions made already that I probably can't add any more. Having had 3 C4s already, here's a few of my thoughts. The '85 automatic coupe was the first and one we kept for 6-1/2 years -- fast and very little trouble with it, even when we got rid of it with 100K miles, to buy a '74 Stingray convertible, which we still have.
The second one was one I searched for 6 months before purchasing...1988 yellow convertible, "Lemon Peel". Like you and your wife, I had a list of "must haves", and this car filled them all -- yellow, black cloth top, manual transmission, low miles (21K). I kept Lemon for 3 years and just recently sold it to acquire the greatest C4 of them all -- 1996 Grand Sport convertible, "The Diva"!!
As many have already said, the '96 is probably the finest of the C4s because all the quirks have been eliminated, at least I hope so!

If only your wife weren't set on an automatic, this is the one for you!! Any chance you can start teaching her how to drive a stick?!
Having had 2 C4 convertibles, I can't stress enough the pluses of having a glass back window!!!! They're so much better than the earlier convertible back windows. Put that on your list!
Of course, price is an important part of your decision making. I'll go along with everyone else by saying...do your research, keep looking for the one in the best condition with lowest miles that fits in your budget. You'll know when it's the right one! Don't get discouraged...there are many, many Corvettes out there!! Good luck...let us know how you make out!
GS Diva aka Elaine