There are calculators you can find on the web that will calculate the pressure changes based on the volume of the tank, and the amount of water that tries to move into the ET. That last part you can get from an ET sizer program. Or, you can look up and run the calculations yourself! Easier to use someone's calculator! As long as it stays below 80-psi, to me, it's okay. I expect the system to keep the pressure within the design parameters, and code say no more than 80. Yes, plumbing devices are tested to a higher pressure than 80 (a WH is tested to 150psi), but the more pressure you exert on things, the more stress you're applying. Some hoses don't like it nor do most gaskets, seals, O-rings.
60psi is what many things like showerheads are designed for, but they will work at different pressures, but the volume they pass and how the showerhead feels will change. Some places would be thrilled with even 30-psi. When I lived in the middle east for awhile, we had an open, atmospheric tank on the roof, and it was all gravity fed at 0.43#/foot of elevation change...you got used to it. A water tanker came by periodically and refilled the tank for us.