The stem splitting, temp manipulation, extended dark period, etc... all these techniques are like @multiVortex said, ‘sprinkles on top.’ ...and that’s at best. At worst, they could potentially be a detriment to a plant in a less than idea environment.
Actually, I wasn't referring to any of those methods. I use a few other bumps that knock it up several percentage points in the long run. Not only on buds, but the sugar leaves as well. Better trim isn't a bad thing what so ever.