I have found that with SSTs you're looking for the trifecta of current divergence, or convergence, then Chlorophyll, then temperature breaks. Temperature breaks are always interesting and you'll find the bait on one side of the temp break. But The current convergence and Divergence is generally caused by structure causing upwellings. I have found that these Current Areas tend not to change much and that using them to identify areas of interest then looking for the otehr two criteria, helps us find fish better.
Light gauge versus heavy gauge, that argument will carry on into eternity. Plenty of fishos are using Light gauge with good effect. But then there are a number of equally good and effctive fishos who are catching plenty with Heavy gauge too, you just don't here as much about them.
With most heavy gauge hooks it does pay to triangulate the barb for better penetration.
But there's even more to it than that there is presetting release pressure for your release clips and light or heavy drags to think about too. Everybody ends up with a combo that works for them most of the time. Then the fish wil change tehir feeding habits and nothing works until you find the new hot combo.
A few years agod when there was a huge amount of fish off the west coast, they were mostly feeding on Saury, so there were plenty of bits, but hokup rate was really low. A lot of people were pulling there hair out with that.