That's good to know mate thanks! I'll have to add some products into the basket with what I have in mind and weigh up the cost, but yes ideally having 2 separate watercooling systems is how I would ultimately want my setup to be. On a side note, would you say that needing your fans to run a bit harder for the GPU to remain at 55c be because the rad is bottom mounted and therefore struggles that bit more to pull air through, than say if it's top mounted? Or would it not make much of a difference?
Regarding my H100i, yes it did start to develop a low weird pitch sound even when I put it in quiet mode. The average person wouldn't notice it, but you know what it's like when it's your own system, you end up hearing and spotting every thing lol. When I first bought it, it originally went into my first M-Atx build in the corsair 280x case and it was top mounted. Same CPU then as I have now. No issues, all working fine. Went to the 570x case, front mounted ... absolutely fine (except this noise started to develop few months in). I very recently top mounted it in my Bequiet case to experiment with fitment, and to my surprise the rad was heat soaking massively. No matter what I did, fans pushing/pulling, remount/repaste etc the temps would be worse in games such as BFV than it would my Dark Slim air cooler. Temps were mid 80's and sometimes see the 90's in BFV. Clearly not right, where as before when it was front mounted in my 570x, mid 60's in BFV. It's like the pump is weakening and struggled to pump properly when I top mounted it. I'd jump out the game and go straight into Aida 64, blue screen. Definitely not right lol.
Sorry for the essay but hence why I want to finally fulfill my goal and go full custom water. Stumbling across your build has given me the kick I need lol!