The first component to be decided is the pump. It should be either AC motor or brushless. There are many transfer pumps, that provide a proper flow rate and pressure, but all they are brushed motors, very noisily and most of them are not designed to work non stop.
My choice was first because the proper head this pump provide, and second because the threaded coupling.
Having the pump the next step was a suitable container that may fit the pump, allow easy removal and in the same time allow me to add fluid without removing the lid. After some search i visit The Container Store and find the perfect one, it has a small cap that is perfect for refiling. On other hand the overall size is very close to the min i need of the pump, i don't think a much better fit will be possible.
I decide to use a triple 360x45 mm radiator. Probably for the spindle and CNC i have this radiator is overkilled and even single 28 mm thick radiator will be a good option, but since i am planing a larger spingle and much stiffer structure i decide on this one.
The rest are fittings and tubes. The pressure is relatively low and push-to-connect fittings are very good option. The only problem i had was the size of the tubes. The spindle i have use 5/16 tubes but finding fittings for them is a problem, at least in the stores near me. I decide to use a 3/8 fittings and 3/8 tubes between the pump and the radiator, and install inline adapter from 3/8 to 5/16 to connect the radiator with the spindle.
The return tube have no fitting on the tank side and go all way to the bottom.
The flow in my system come from the pump, going troughs the radiator then to the spindle, and from the spindle return to the thank. This is not the optimal solution since the hot coolant is returned to the thank. Swapping the radiator and spindle places in general is better, but for the arrangement i have this looks nicer and having on mind the overkilled radiator should be good enough.
To secure the tubes and the pump cable i used a plastic cable glands, or as they described in Menard cord grip connectors.