Reps are your weekly lever
Double progression is the cleanest method. Pick a range like 8 to 12, add a rep or two each session, and only bump the load once you hit 12 on all sets.
Add reps within your target range first, then add weight when you hit the top, and add sets only to raise total volume.
These are three different tools. Add reps first: stay in your rep range, say 8 to 12, and add a rep each week until you reach the top. Then add weight and drop back to the bottom of the range. Add a whole set only when you want more weekly volume for a lagging muscle, not as your weekly progression.
Double progression is the cleanest method. Pick a range like 8 to 12, add a rep or two each session, and only bump the load once you hit 12 on all sets.
When you reach the top of your range with good form, add the smallest jump, roughly 2.5kg on a barbell or the next dumbbell, and rebuild reps from the bottom.
Adding a set raises your weekly hard sets, which drives growth up to about 10 to 20 per muscle. Use it to bring up a lagging area, not every week.
Add reps within your target range first, then add weight when you hit the top, and add sets only to raise total volume.