Most people see spacers as a bad idea.
You can get spacers from Ecklers. www.ecklers.com
There are aftermarket wheels avaliable that have the correct backspacing for our cars without spacers and look like ZR1 wheels. Take a look at the #290 Vortec Z wheel at Performance Wheel Outlet. They advertise in the Chevy High Performance magizine.
Go to the portal on the top of your CACC screen and click there. You will be able to search all kinds of places for wheels and spacers.
The Vette Brakes and Products spacers are very high quality. I don't think you will have any problems with them. A friend of mine got the spacers to put the ZR-1 rims on his 85 vette (different offset from 84-87, then 88-96) for the front of his car and they work great.
Welcome to CACC. I would love to see some finisheds pics of that. In the future we may have a wheel selection program here where you can swap wheels and paint colors to see what they look like. However, it may be a C4 body style at first.