Swarren, thank you for the suggestion. I spoke with sales and they recommended that I download the trial and then call the customer support line. CS had me download a few sample plans and then create some perspective 3D views to test my machine. It worked fine and I chose to buy Pro 2018 at my risk knowing that my IMac is below their recommended OpenGL version.
I will proceed with using the program and will provide feedback as after I use it for a while. So far, so good.