I'm running 2x 360 radiators with Vardar fans with an overclocked 8700k 5.2GHz and a 1080Ti and I think that is a bout the minimum I can run when playing BFV on the extra hot summer days unless I want to crank the fans up a little in which case I could run a 360 and a 240. I have the EK-XRES 140 Revo D5 PWM running at 40-45%. Any faster and I can hear it. Not loud but it is right next to me and I don't think faster cools much better.
When water cooling a bigger case can be better especially when you want to reach into the case and change stuff without the pipes and pump getting in the way.
I am changing one of my radiators to a 420mm and fitting 140 furious varders to give even better cooling.
You could start with a single 420rad and 140mm fans and see how you go but either way my preference would be for a larger case.
When you hold a 140mm fan you realise how much more substantial it is than a 120mm fan