It varies plane to plane, some 'need' the nose pulled down more than others.
Some pilots will pour scorn over you for using any curves, but I'd be surprised if anyone flies actually flies a Dr1 without pulling the nose down...
My rule of thumb is near level flight, with a slight bias to climb. (obviously this is relative to a particular speed - your plane's lift should increase with speed and vica vera.
HillBilly's graph looks text book in the way he's smoothed out top and bottom after placing the 'pitch point'.
Beyond that with a little experience you'll start to feel if a particular plane needs specialised tweaking.
(As a side note there may be one or two planes that have a particularly strong reaction to stick forward (Camels !!).
That being the case I'll slow the initial response to that a bit with a negative S Curve so the top and bottom halfs of the graph will look different.)
Only mess with the curves when you identify a need to, you'll soon get the hang of it.
Good luck !
".. and they'll send you home in a pine overcoat, with a letter to your Mum,
Saying find enclosed one son one medal and a note, to, say, he, Won".