2 pixels now. I would like, at least, either 5 or 6 pixels.
In this sort of situation one wants to overshoot and then adjust inside a bracket. IMHO
Doing deletions or drag and drop critical decisions and moves are made. Until recently I have been blessed with 20/20 vision but I have made some really bad blunders - not reading the tree and lines correctly. When I make an error and then continue on - chances are excellent that there is NO GO BACK function available. I would carefully study the address line and depend on it before taking any action. A good tree and more distinct lines will be fare more efficient.
From you reply - can I assume there is no menu available to make adjustments? I, and many others, have lived for years without knowing how simple it is to change the tree pixels. To me it is a vast improvement THANKS.
A non black screen probably requires thicker lines. Please give it a go!

5 or 6 pixels