Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.
The only thing that really matters much is to have the pump after the resevoir (and below it helps too). This is more to facilitate filling and bleeding the loop, but also to help the pump get as much water as it needs. Restriction on the pump inlet is bad for performance.
As for the radiator, if the radiator is in the top you can get air bubbles in it, but all you have to do is tilt the case around a few times to get the air out, so it isn't really an issue.