Originally Posted by annul
You should be able to mount your reservoir on the bottom radiator fan using this: https://www.ekwb.com/shop/ek-uni-pump-bracket-120mm-fan
That should give you enough clearance to fill. EKWB also makes multi-port reservoir tops that you can buy separately, which might make things easier for you as well if you don't want to use the pump top inlet.
For your radiator, you might need to get new screws from a hardware store but make sure that the screws aren't long enough to puncture through the channels in the radiator
. These radiators don't have a mechanism to prevent you from doing that.
HWL labs should have a protector to prevent this. Also the solution to longer screws is to ether cut them to custom length yourself, easy enough to do with a Dremel, or buy some washers to make up the extra length.
Welcome to water cooling. You learned the first lesson, you can only plan so much until you get everything and actually set it all up, At that point the plan is out the window. It only took me 2 and half months to finish my loop, plans be dammed.
If able it's always better to buy more and not need it then not have it when you need it.