Conditions are important in hook selection, but ultimately whether you land the fish is the most important consideration. I had a poor hook to land ratio using 1/0 hooks and saw a great deal of improvement stepping down to size 2s. I generally fish deeper, bouldery water where longer leaders are an advantage, and I've never been one to have that whistling hook set. So I don't think I was getting good hook penetration with the larger hooks and barbs. With the size 2s, I feel I get better penetration and I also think the fish holds onto the smaller presentation longer. The drawback of course is the smaller gap not finding a good hard spot to hold in the fishes mouth.

The tradeoff seems worth it because I do land more fish than I used to. The only time I go to larger hooks is when I'm fishing fast water or just above, when I know I'm going to have to put on the breaks.

I use Gamas; haven't experimented much with anything else, but I've noticed that Gamas have a smaller barb than VMCs or mustads.