It is gorgeous!!! I much prefer rectangular to square as well. But we already knew we had similar taste in jewelry!! 😁😋 I think it'll look fine with being dressed up, I can def see it with your diamond bangles on one arm and your watch on the other looking gorgeous and elegant. If you want it to be more formal, maybe consider a leather or satin strap? And you wojldnt have to buy a cartier strap, my jeweler has both non and cartier (as he is an authorized dealer) and the non look great as well. Or maybe add some type of diamond bracelet or ring on that hand?