My advice on the overflow tank is to get one that shows the fluid level without taking the lid off. Plastic ones are the best for that although another member recently posted a photograph of an aluminium one with a sight gauge on the side. One should still occasionally take the rad cap off and check the rad is actually pulling the fluid back into the radiator. The shiny steel ones may look nice but one has to take the lid off to see what's inside. Also get one large enough to do the job. Mine is full when hot but completely empty when cold. The radiator is always full, the tank holds exactly the volume the rad expels when it heats up. I have to take the top if the tank and the rad cap off to check the level. PITA. I'll attach a few photos of one too small.
As for the radiator be aware that if you get a hole from a stone, or whatever, in your aluminium radiator you may not be able to repair it. Get a hole in you brass radiator while on a road trip and the nearest garage can most likely solder it closed. Not so with an aluminium radiator.I had to replace mine for that very reason.