thanks for all the imput guys. just something that crossed my mind.
if I would do it I would go with GTR lights, because of the offsett diameter but will keep the mod as subtle as possible. the convertible does not look good at all.
When I was trying to decide on a car project I had ideas about getting a Camaro and switching to round taillights to imitate a 72-74 Cuda. I ended up buying a 73 Cuda. As other's said I haven't seen a Camaro with round tail lights that I really liked. Perhaps look at using Cuda lights if your set on it, I haven't heard of anyone trying them out. I think the sculpting in the tail panel around the Cuda's lights helps them look right.
I am now really liking the square/rectangle tail lights of the earlier Cuda's and Camaro's. The grass is always greener.