Trial and error works for me.

Get the reach right and where you normally ride on the bars. Then the saddle height and fore and aft.-----Basic fit in other words. Saddle position will set the sit bones on the wings of the saddle and then I tilt the saddle till I am only just resting the pubic area on the saddle. I can just feel it in other words. This normally means that I will be sliding forward on the saddle so raise the nose till I stop sliding forward.

I say trial and error as it is different from bike type to bike type. The two main road bikes I ride do have the saddle parallel to the ground- which surprises me as bar height in relationshio to the saddle is different. But the OCR which gives me a more upright position-Bars level with the saddle and a shorter reach to the bars- Does have a degree or 2 of uplift on the nose. The MTB has a degree of down on the nose. and the Tandem is parrellel with the ground. I don't worry about how it should be set up- My butt tells me when it is comfortable.