I'm a long way from having a real idea about this (I'm about your level!), but I believe.....
1. Stronger pull - low 20s, or 20ish, I think. May depend on the session(?)
2. Around 4 or 5 is what the good people use. Before the session, if you're on the same model I use, you can press a couple of buttons ("rest" and "ok" perhaps???? I need one in front of me!) simultaneously and the drag factor will appear like magic on the monitor - 130 drag is about the ballpark - depending on cleanliness and other things, the slider setting is very machine-dependent, but the drag factor is absolute.
3. Uh... ah.. er..... I decided to stop improving soon after my one and only 2K time trial! Horrible!
More usefully, there's a forum on the
Concept 2 website which is a touch po-faced and ego-driven compared to this one, but there's very useful help there.