Which Tyres?

Easy answer-no.
just trial and error, what you find comfy without tyre squirm. What you find comfy and what I find comfy may be completely different, I run 28s for commuting at about 80psi, ran 32s at about 60-65psi, 35s at 50psi.

Personal preference, also what @jontea explained it perfectly;

what you find comfy without tyre squirm.

My recommendation is to put it back up to 70psi so you can get used to it, as it'll still be comfortable than 95psi.

It take a while to get used to it, especially with the old conventional wisdom of higher pressure = feel faster (in reality it's the exact opposite).

And one last thing, as it is a personal preferences (and depend on your weight, heavier rider = higher pressure), it also based on what kind of riding you do.

Commuting, usually a little higher than usual, especially in London where you're likely to ride slower and thus more prone to getting caught hitting potholes, also slightly less squirmly at a lower speed.

Country riding, you can get away with an even lower pressure (I ran 40psi front, and 50psi rear with the 28mm) as you'll usually go faster and float over poor road surface easily.

And of course, the other outcome is how much you're carrying on the bike that may required a higher pressure.

yes, frank berto tyre pressure chart gives you an excellent starting point, I've used this quite a lot, clearer it's just a guide but in my opinion it's a very good one to work from and takes the guesswork out of getting it right for yourself with respect to comfort/rolling resistance.
http://problemsolversbike.com/files/blog/BQ_berto_inflationgraph_2.jpeg