Make sure that you don't skimp on your power supply. Nothing used, and be sure that you have plenty of power on all rails for what you're doing. Although PSUs are not the sexiest part of a new rig, and don't get the publicity of the CPUs, GPUs, mobos, etc. they must be good. Cheap or otherwise flaky PSUs are a major source of intractable problems. For example, I used an older power supply on my new rig. Until I bought a new PSU, the machine was very temperamental: one day it would start up and run fine; another, it won't power up at all. I got so frustrated yanking components in and out trying to isolate the problem that I snapped an anchor off of a memory port. Problems like this are the LAST thing you need with a trading rig.
G.Skill is superior to Corsair for memory. Also other lower end Corsair products like PSUs are of poor quality compared to competition. Never understood why they are liked.
find yourself a refurb name brand xeon quad core or better, six core show up on ebay, stick with intel, HP, lenovo and Dell etc. Use this as foundation. Add SSD, more RAM, nice text base graphic card(s) to support 4x4k monitors. Save yourself some $ and build a kickass workstation for a fraction. Stay away from consumer game hardware, don't pay for something you'll never use.
You would be wise to start with the motherboard, heart of your system, than choose from their recommended memory, website or MB manual. could also call there tech for 2nd option on memory. Just my opinion, In addition, Multi monitor video cards are always compatibility risks, just a heads up.
I wish I had your problem like one of the posters said here really, just spend to the max since you gonna be trade for years and that's really it. Don't over complicate the issue and that memory is really for gamers anyway and for doing so don't do it.