Many users have not been happy with EK Vardar fans. I do not advise them. The PH-F120MP are really about as good as it gets and even not on special are lower priced than others. Probably the very best are Noctua NF-A12x25 PWM but they are £29.99 each.
AIO and CLC are not better than good air, cost more, usually make more noise (pump definitely makes more noise at idle than an air cooler at idle), are extremely cheaply built, can't be repaired if something goes wrong (almost always the pump) and when pump fails system is unusable until cooler is replaced. CLC pumps and no fill port are CLCs' worst problems. Pumps are only capable of flowing about as much coolant as a healthy adult can **** after a few pints (40-60L/h) compared to D5's 1500L/H (D5 is arguably the most popular custom loop pump) and hopefully you get an idea of how little coolant CLCs flow.
Your RL06 supports radiators as follows:
Front 120mm / 140mm / 240mm x 1
Rear 120mm x 1
Top 120mm / 240mm x 1
Top only support a total thickness of rad and fans of <30mm .. I don't know of a rad & fan combo that is that thin. This means you are limited to a 120mm rear rad (definitely not enough to be overclocking on) or a front 240mm rad with it's heated airflow dumping into case onto GPU if used as intake .. meaning case would have to be setup with airflow from back and top to front exhaust.
The best way forward is good air cooling. I see peeps who switch from air to CLC or started with CLC who are no moving back to air cooling either being extremely happy they came back to air or amazed at how much better (quieter) as well as often cooler a good air cooled system is compared to CLC. Below is what a x-CLC user said yesterday after installing air cooling .. (FYI, Liqtech 360 has 360mm rad (3x 120mm fans) and only one with pump that flows up to 450L/h).
'I am a perspective guy. With that said, I am in awe that I have a Stable 4.025GHz OC being air cooled. No interest in water. As somebody once said...water and computers don't mix.:woot: I have no time for a custom water loop. When I originally built this system, I chose the Enermax Liqtech TR4 360 and had to RMA twice because they are garbage. I don't want to obsess about my temps. Taking the rear exhaust fan off helped a little. I'm keeping the top 3 exhaust fans. At stock speeds, the 1950X rips through video encoding at high quality settings. Overclocked to 4.025GHz makes a noticeable speed improvement but not an earth shattering one.'
Most of what people call AIO are really part of the sub-group CLC. No CLC has fill port nor any way to service or repair it. There are a few AIOs that are not CLC like Swiftech, Alphacool Eisbaer, be quiet! Silent Loop and Fractal Design |Kelvin but I think Kelvin is no longer being produced. I would not buy Alphacool because of some of the problems owners have had getting customer support when they had legitimate problems with product, but be quiet! gives good support so if you want AIO that would be the one to get .. or Swiftech, but Swiftech is had to find outside of USA.