I usually hold the rig up to check the setup. When the weight is dangling on the bottom, I want the hook to be around 0.5 to 1ft above it. My leader is usually only about 1ft, perhaps a bit longer, so the length of line trailing to the weight is about 1.5 to 2ft long.
Hook size for salmon when bottom fishing with roe, I use size 1, 1/0, occasionally 2/0. All these sizes work well for chinook and coho salmon. Other factors determine which size I use. For example. if there are small trout around, I try to avoid using really big hooks so I don't end up hooking one through its head when it bites, which would instantly kill the fish. A hook that is too small is also not good if the chance of catching big fish that I need to release is big. Deep hooking a fish reduces its release survival rate significantly. Generally, size 1 is a good one to start with. It worked well for me last year when bottom fishing with roe for coho salmon in October.