Filling - from where?
 

Consider the following possibilities of filling system (a reservoir is the highest point, the inlet is higher than the outlet).
1. Through a hole in the lid of the reservoir.
2. Through "T connection" - in the inlet of the reservoir.
3. Through "T connection" - in the outlet of the reservour.
4. Through "T connection" - in another point - where?

What way is better?
Thank everybody.

well i'd say make your life simple and just use a lid of the resivour but it might be too tight of a fit so i'd say a T junction right near the res, i dont think it'd make a difference where exactly, just somewhere near the res. hell a 3rd hose directly into the res would be an option as well...

if you use a T juction anywhere else than that, now that i come to think of it, your alsmost setting up an inline system that has a resivour. now that doesnt make sense but that esentially what your doing, and it doesnt make much sense

Any of them will work. Personally, I'd try to use a T where it'll feed the pump inlet (even if it's through the waterblock), because that's where the coolant needs to be to get things started.