Actually, when I ride with my wife/luggage the bike is quite stable: the problem is when I have only the luggage. Do you have a similar experience?Maybe the suspension/tire brand and pressure, combination does not work for you. Been riding 2 up with the wife and luggage. The front felt lighter and leave the ground under heavy handed acceleration, and in general the bike felt softer and less responsive, especially on twisties, yet, handling was solid and predictable. I ride angel GT f35/r32
PS: funny, I have almost same pressure as you, but reversed: lower on the front. I've seen that high pressure at front tire reduces stability, although now I'm curious to try it again.