OKO I usually watch the new dot drift (right or left) and follow the pointer of the cursor on to the last LOB.
Hope thats right - seems to work. Then as you get more LOBs you start to build up a picture.
But here its important to watch the fan to see if your in lag or lead . Seems that if you can maintain lag you build up an accurate picture
Like Raf I build scenarios with targest on zig zags and practise. But still I am, like many, shakey in high density situations.
Little point extra I have to watch is that in SCX by default the update times are set at 20 mins.
Dont know why - but first thing I do is to right click on the display and set 10.