Rubber hoses are much better inside coolers imo because they act as shock/vibration absorbers. Could be quite a noisy shaky cooler with the pump lines solid to the cooler case/exchanger.
the pipe is 3/16" brake pipe and the fittings are 1/4" bsp, I made them for that cooler. the nuts were put on the pipe before the nipples were soldered in place
I totally agree with Richard.
Flexible hoses are the way to go, I think too.
All the coolers I opened so far uses them. EWM, Fronius, Hitachi, Weco.....
So why bending copper tubes cutting it to exact lenght and soldering....
If you have to change the pump or radiator for one reason later to another one with different size, you have to do it again.
Much easier with rubber hoses.