IMO hook size has more to do with how well you hook up than does that last bit of sharpness on your point . Even a nice sharpened gammy , say in a size #1 , requires more force to set in than a moderately sharp #4 due to the thickness of the hook itself . You need to remember that that sharper point is followed by a thicker shaft of steel that resists driving in more than a thinner hook . My #4's are always nicely buried and don't come out nearly has often than when I used to use bigger hooks .
penn, you've got a good point there.
Are you using #4 siwash for colorado spinners or is the #4 hook for bait fishing?
In my case, I use the siwash for spoons and french spinners, and most of my catch this season was using either a #5 silver french spinner or 3" chrome croc-like spoon.
In these cases, I will normally use #1/0 gammie siwash for the french spinner and #2/0 for the 3" croc.
I like to use big and flashy lures when water temp is lower as my target is the most aggressive and fresh fish in a pool and also big lure is needed to temp a salmon to strike when their metabolism is low. I even have a 4" croc, but seldom use it as it would scare my fellow anglers more than the salmon. LOL.
I have not tried it, but I think using a #4 siwash on a #5 french spinner or 3" croc might be on the small side.
I know I could go smaller then now, but by how much?
Cohos are gone now, so I guess I will have to wait until next fall to find out.