I asked the question about tire pressure recently, and someone posted a link to this article: https://www.adventurecycling.org/res...SIRX_Heine.pdf

Basically there the tire pressure is based on the weight on the tire and the tire size itself. You would need something like a bathroom scale, and someone to help hold you up steady as you sit on the bike with the scale under each tire to see what the weight distribution is, and then use that to determine optimal tire pressure for the front and rear tire.