Most times you are at the mercy of the wind and currents when it comes to jigs.
I've done lots of jigging.
The deeper you go, generally you have to go heavier jig . I'm often down about 130ft.....and the small jigs will just not stay down there due to current,wind, boat drift.
If the wind is blowing opposite to the current that makes it worse if your boat is drifting.
The jig design factors in too. Small buzzbombs flutter too much for deep use.
But often other deep jigs sacrifice action for the ability to get down there.
I use 50lb tuffline with a 6ft 30lb mono leader........I was using 80lb but even that can be affected by current.
Mono line you don't get the feel and responsiveness for bottom hits.
You go heavy line , you get too much current blowback.
For Lings and big Rockfish......it's ok to use a large jig.......often I just use a big Spinnow, 8 oz or bigger ....they will hit it no problem.
Sometimes small bait is good........but like you said, it's so dang hard to get a small jig down very deep in a current.
The days that you get those allday low,low tide drops are usually best for that.
I mostly use the small jigs inshore for GreenLing...when I only have to be down 30 to 50ft..
Spinnows seem to be better at getting to depth than Buzzbombs.
There's a guy in Port Alberni that makes a jig called the "Budzilda"
This jig flutters even more than a buzzbomb.....and it is a deadly jig......even works on Sockeye in the inlet when they are schooled up.
But it's too fluttery to get down deep in a current.......even in the bigger sizes.
For bottomfish...usually the response to jigs is a good indicator of how much bait is around.
If there is tons of small minnows and bait around.......I will have a slow day.
Because they are already gorged on real bait.
Some days I go out jigging for bottomfish in the hotspots and it's like a wasteland.
If not much bait around....they are hungry and you will get lots of hits before the jig has had time to hit bottom.
Strangely I often do better when there is a current running than on a dead slack tide or low current.
Salmon are pretty picky it seems......I've probably made at least 400 jigging trips over the years, in areas where there are salmon, using salmon jigs, in depths from 30ft to 240ft. off ECVI......
Caught tons of bottomfish legally......but the number of salmon we've ever caught on jigs:- 4
But then again the jigs were usually on the bottom....
A good way to jigfish for salmon is drop the jig through a baitball.
But honestly...if I had to rely on finding a baitball to fish...I probably would not have gotten anything......the baitballs are just no longer there in any significance where I fish......I can go 6 hour trips with the finder on and never see one.
This year there is more bait around though........but I have still yet to see the magical baitballs anywhere.