[Freesurfer] multiple correction

Hi, freesurfer expert, I have three questions about the multiple correction.

I performed the statistical analysis between two groups first in left hemisphere, and got some regions which showed different. 1) so if I then do multiple correction, i don't need to run the mri_glmfit-sim command, and just press the button of the monte carlo null-z simulation in the qdec interface, am i right? 2) Whether mri_glmfit-sim --cache command line and the mc-z in qdec get the same results, or not? and as to the option --cwpvalthresh, should i choose 0.05 or 0.025? 3) And what is the difference between fdr and mc-z correction? Thanks, Meng