Need some help with my timing curve.

^^That's^^ more specific advice than I could give for a 5.9 not having messed with them.
The target range I posted in those other threads was specific to the person's application.
The shape of the MP small block advance is generally about right for a 4 bbl LA engine w/ a 4 bbl cam, or somwhat hotter aftermarket cam. etc.
A more efficient burn under load, for whatever reason, in any part of the rpm range would reduce the lead time needed at that rpm. That could be more efficient heads under high flow conditions (less timing at higher rpms), it could be more heat in the upper part of the cylinders and combustion chamber, etc etc.

Only thing I would add to TT5.9mag's guidance is that there is rarely a reason to hard stop the advance at 2800 or 3000 rpm as long as its advancing slow enough.
The various long looped heavy springs Chrysler distributors came with is the secret to the two stage advance that creates a curve like the one in the MP distributor I plotted out.