There are several anglers who tie their own leaders, I am not one of them, do not have an aptitude for it. So…I purchase pre tied leaders for my salmon fishing. The time of year and size of bait, (cut plug herring), I am using will determine size of hooks and # test line I choose. I prefer the slip tie rigs, so I can adjust the hook placement on each bait.
For spring Chinook fishing I like a 3/0 4/0 hook size with 20# test line, I am using green label herring with this selection. For fishing the ocean I like a 4/0 5/0 combination with 30# test line, also with green label.
A lot of anglers will use red label for springers, when I do I go to a 2/0 3/0 combination with 20# test line. Every angler has their own brand preference, and their own opinions about hook and line sizes. I use Gamakatsu Hooks.