SMPS chassis ground and earth ground

I'm designing a ultra low noise smps and I have some questions about ground/earth chassis. The main goal is very low noise on DC output.

1. Earth (PE) should be connected to one point (only) to the chassis ground?
2. AC line usually has two Y capacitors after common mode choke connecting earth. This connection should be at chassis or I should connect to single PE point (as in question 1). What's the best value for those Y caps?
3. Primary side and secondary side transformer have Y capacitors connected across. Should I keep those if I use earth/chassis (I assume I will keep them in place since I want a short path for noise to return)?
4. DC side ground. In some designs I see it connects to chassis (that's connected to PE) using capacitors. In other designs I see it connects direct. What's the best way keeping in mind original goal?
5. DC side. I see that even the + is sometimes connected to chassis ground using capacitor. Should I make two connections to chassis ground on the DC side or should I take both (using wire) to single point connection (where earth connects to chassis)?