I saw the water cooling thread with all the links, a lot of which are several years old....  EDIT: YES, I'm still going through them.
 
So, I have a few questions here with a couple sub-parts: looking to rebuild my current rig - upgrading the CPU to I9-9900K, and GPU to EVGA GeForce RTX 2080 Super FTW3 Hydro Copper Gaming, double the RAM, and do my first full custom watercooling setup at the same time. Using it for 4K gaming, and 4K video editing. - build timeframe - potentially 6 months or less - but might wait till next gen nVidia release.
 
# 1> What are some of the SMALLEST cases that will fit both a 3x140mm radiator and a 2x140mm radiator. I don't want a gigantic case, prefferably under $300 - definitely no more than $400.
1a> are copper rads much better than aluminum rads?
WIll be utilizing Noctua NF-A14 iPPC-3000 PWM fans on the rads. Would like to re-use my Corsair Air540 but pretty sure a 3x140mm rad will not fit with a RTX 2080 installed.
 
# 2> What I've envisioned in my head is this: pump > GPU > 3x140mm rad > CPU > 2x140mm rad > res > pump. Overclocking the GPU, but not the CPU - or at least not right now.  Is this a good route to go with?
2a> Would I be better off running 2 systems in one case i.e. Sys1 pump/rad/rez/GPU - Sys2 pump/rad/rez/CPU for when I do decide that I want to crank up the CPU?
 
# 3> Is FrozenCPU still a decent site to use for liquid cooling gear/parts in the USA, if not who?

Thanks!  Looks like EK has almost all the info I need