Automobile Enthusiasts

In general, the simulation software is pretty good to A/B 2 choices. The better the information you cam use, the more accurate you can be. EA Pro lets me get to a serious level of detail - like flow numbers at 5 different valve lifts, and similar data for cams. Rod length, combustion quench, collector taper - great for an obsessive like me.
If you are dealing with pretty mainstream stuff, I think Desktop Dyno will do OK for you. The basic engine files for stock configurations of popular engines are gonna be pretty close, and the same for popular series of cams.

In VERY general terms, your original questions: overlap/lobe center - decreasing lobe center increases overlap. Wide lobe centers are better at low rpm, and may help top end a bit. Conversley, Narrow lobe centers help midrange, especially if the torque peak is in the midrange as well - but the whole range ain't all that big.
Advance/retard - advance tends to move the power peak lower, cam retard moves the peak higher, As timing chains stretch, the cam retards - so, if anything, you want to shade a new build a couple degrees toward advance, so that it will come right as the engine breaks in. A lot of mild cams thes days have 2-4 degrees of advance "ground in", They seem to work best in this range, and this allows them to be installed with a normal timing set and hit the mark most of the time - and if tolerances stack, they won't end up retarded. Retard tends to not work out well for any sort of "normal" combination.