Screwing IN either screw reduces the travel of the DER.
You would probably want to try about 1/4 turn on the H screw.
Keep track of HOW MUCH so you can revert, in case you turn the wrong one. TOO MUCH, and it won't shift from 6 to 7.
Screw the L screw in too far and it won't go from 2 to 1. Too far out and the chain goes into the spokes.
For "fine tweaking", turn a little bit and RIDE the bike, going through ALL the gear combos. I like to hit a couple SMALL bumps also, just so things are fully "settled in".