

You should ask this in a CAD dedicated subgroup. I’ve been running high-end CAD software (I-DEAS, UG NX, Solidworks) on low to midrange PCs since 2000, and never had any issues. I don’t know of any CAD system that supports the high-end features of the graphics cards you specify. There are some advanced rendering packages that might, but those cards aren’t necessary. You might just get your pretty picture faster.
If you’re going to be running FEA or simulations, just pack as much RAM as you can. 32Gb minimum.
Exactly. Windham isn’t going to do anything until you make it inconvenient for them to ignore you. Do whatever you can think of to be a nuisance with the information they send you.