New here as well but I've built several watercooled rigs. My thoughts, go with a Pacific PR22-D5 pump w/silent kit and a 420mm or 480mm x 30mm radiator. Keep in mind, the thicker the radiator, the more static pressure you will from fans. Currently in the process of building a new watercooled rig myself with a View 71 case and using a R9 3900XT CPU and RTX 2080. Since this is a fairly large case, I'll be using two 360mm x 30mm rads with the PR22-D5 pump/300ml reservoir combo w/ silent kit.