Build advice

[rintintin78]

Hi, I would like to build a new custom liquid cooling loop, but I need some clarifications. My PC specs are an RTX 5090, a 9800X3D, and a Havn HS 420 case, with an Alphacool VPP Apex D5 pump. After doing some research, I have a doubt regarding the configuration. I have two options in mind:

1. Two 420mm x 30mm radiators: one on top and one on the back, equipped with 140mm T30 fans, both set as intake. Additionally, three 140mm T30 fans on the side as intake, and two 140mm T30 fans on the rear as exhaust.
2. Three 360mm x 30mm radiators: one on top as exhaust, one on the back as intake, and one on the side as intake (all radiators equipped with 120mm T30 fans). Plus, two 140mm T30 fans on the rear: the bottom one as intake and the top one as exhaust.

I checked the W/10°DeltaT values on the Xtremerigs website based on my specific needs (@1.0 GPM and fans at 750 RPM). The values are roughly 175W for the 360mm radiators and around 230W for the 420mm ones. According to my calculations to dissipate 700W, the coolant temperature difference between the two setups would only be a few degrees (2 to 3°C).
However, with the two-radiator setup, I will have more fresh air entering the case (via the 3x140mm side fans), meaning internal components (motherboard, RAM, and SSDs) should get lower temperatures. On the other hand, with the three-radiator configuration, even though the liquid temperature might be slightly lower, I would only have one fan bringing in fresh air (the bottom rear 140mm), while all the others would be blowing radiator-warmed air into the case.
Could you help me understand if my reasoning is correct? If not, what mistakes did I make? And would the internal case temperature with three radiators really be bad enough to justify giving up those 3 to 4 degrees on the coolant?
Thanks!