The weight of rider + bike is a factor that you might be forgetting though.
The more weight you and your bike add up to, the more air volume the tyre needs as a cushion against road conditions. A given amount of air is always going to fit in a bigger tyre at a lower pressure, and have more grip and handle rough surface better, though at a weight penalty.
I use a rough formula: the bare minimum tyre size for road going bikes is weight in kg of you and bike divided by 4 and then add 3mm to your result.
Then, using this rough chart (I understood a bit), you can work out your pressures and weight distribution.
Keep in mind this is a chart for weight on one wheel and not total weight, so you'll need to find your weight distribution out via a scale and simple maths.