The connection from the reservoir/pump to the rad is between the three choices of either:
A. 10mm copper pipe with 5 90 degree bends:
B. 10mm copper pipe with 2 90 degree bends:
or C. 13mm flexible tubing with 2 90 degree elbows.
The pipe will be chromed copper rather, those in the pics above are just test pieces. Still not sure yet what to go for. More info can be found in my build log, link below!