I use stock trebles on Blue Fox # 4's and 5's. I don't think there's a spinner and hook combo I've used (and that's many) that has a better bite-bank ratio (steelhead) for me than the #4 Blue Fox with the standard treble. It's in the 80% range. That said, when using trebs, I use moderate action rods in the 4-8 or 6-10 range and let the fish go bonkers for a minute before I put the screws to them. However, I only like those spinners under certain conditions. When I throw torpedo styles size 4 and 5 or larger spoons, I usually use siwash and usually Gami's in #1 or 1/0. Bigger hooks hold big fish better. I like the VMC point, but have straightened too many. I've missed too many or quickly lost them with sickles. With smaller spinners, like #2-#3, I usually use Gami trebs and currently like the short shank, as it's stronger than most. Trebs definitely have a better hookup ratio. One thing that helps reduce snags with a treble is forming the lure with pliers so that there is an eye for the leader that's off center. When attaching the hook, have the welded point on the same side as the leader eye. That will keep the welded point straight up and keep the other points from pointing straight down. (You can do something similar with siwash). IMHO, the treble-rigged spinner will track straighter and spin a little slower than a siwash equivalent.

Regarding trebs being hard on the fish, I've had mixed experiences. The trebs are more likely to cause bleeding for sure, but the siwash often exit the corner of a steelhead's mouth through the eye socket, especially on smaller fish. I've seen this with every brand, including the sickles and down to #1. I'm not sure what the right answer is, but my response recently has been fishing smaller lures with smaller hooks regardless of hook style. I've landed many steelhead in recent years on the #8 trebles stock on some smaller spoons. It's all in the rod action/power and following the fish to leverage them sideways IMHO.