Mac OS High Sierra and Sierra are versions of macOS released by Apple.
Mac OS High Sierra and Sierra are versions of macOS released by Apple.
Got it, just purchase an internal storage unit. You're limited by a 480Mbps USB port (unless you're using a trashcan Mac Pro), which usually reaches about 40MB/s and struggles with IOPS. NVMe options won't work.
Get High Sierra, generate a bootable USB, start it, and install on your desired drive.
You're wondering about using a Mac Pro with a trashcan setup. It seems like you're concerned about compatibility, especially since Ivy Bridge-EP doesn't support NVMe drives. A regular SATA SSD in a USB3 enclosure would work better, and TB2 cases are usually overpriced without significant performance gains.
And it's not that I bought a Mac Pro yet—I just got one by paying $100 to my friend at the local store. He said I should pick something, so he recommended keeping one. If I chose the iMac, he’d add those $100 to my current model. That deal sounds pretty good!