Drop Shot
The majority of my big smallmouth fishing is done on the St. Lawrence and Lake Ontario (Canadian side). The fish traditionally sit anywhere from 10-50ft of water. My main method is the Drop Shot. I use a VMC Spinshot drop shot hook. Go too line would 8lb Sufix Elite. You can comfortably downsize to 6lb but check the line after each cast if you're fishing around current and rock. For weight I usually end up throwing a 3/8oz. It is quite common in some of the harder to get, honey holes, to throw down a 1/2oz weight because of current. I want my soft plastic to stay in place a lot of the time and just bounce it momentarily (not gospel, just a strategy I've found effective). If I use a scented plastic, all the better. It almost always increases my hook up rate no matter the conditions. Look for no further evidence than Josh Bertrands 2018 Bassmaster Elite win on the St. Lawrence. Josh was using the 4" Berkley PowerBait Max Scent Flatworm and the 3" Gulp! Minnow. I have used the Gulp! Minnow on the St. Lawrence and it's definitely a producer. I truly believe scent is a major key in the drop shot method. Finesse worm, minnow and leech style plastics work best.
Rod - 7tf. Anything Medium, Medium Light with a fast tip. Some guys up here prefer extra fast tips because the Smallies have a tendency not to smash a drop shot, they'll just pick it up. You'll get the odd crack but its not a lot.
Reel - A spinning reel 6:3:1 will do fine. I've used a Daiwa Revros 2500 for 3 yrs now. Simple reel with an excellent drag! Worth a lot more than its price in my opinion, but I am biased.