Which switch should be same to get the same 2-pass result?

[galaxy001]

When run a 2-pass or n-pass encodering, some switch can be ommited or lowered in the 1st or n-1 pass, and megui suggested some, like -rdo and -me hex.

I want to know which are they.
I don't know whether some lowered switches will cause a different Q value or frame type compare to a 2-pass with the same switches.