I do not know why, but, I will offer what I would do in this case even though it is difficult to say for sure since I am not there to really see the water. From the picture, it looks like the angler is downstream of the hole and if this is correct, I would slowly hug the left bank and ease up closer to the actual hole which I am assuming is the darker water above the light tan water. Once up closer, I would first drift a weighted Murray's Stremph through the hole with the first cast landing at the top far left in the picture and let it drift as close to the far bank all the way around to the tail out of the hole where the darker water meets the tannish color. Next cast I would start the Stremph at the same starting position as the first and swing it through the middle of the hole. With both drifts, I would add a few 3 inch strips to the Stremph throughout the drift. If I am incorrect and the angler is upstream of the hole, I would probably drift an un-weighted Murray's Stremph through the hole with added little strips to make it look as though it was trying to swim upstream. In both cases, I would try to keep the Stremph drifting as close as I could to the bottom of the hole.

The above is what I would do from looking at the picture and I may do something all together different if I was actually there.

I will not respond to the rest of the question about spinner and worms since I have never fished for trout with either one and do not ever see myself doing it. Not that there is anything wrong with others that do fish that way. I enjoy the challenge as much as the "catching" when trout fishing and, in my opinion, there is more challenge with a fly rod and fly.