[Freesurfer] some very basic Recon-all questions

Hi,

When running something like: "recon-all -autorcon1 -i file1.nii.gz -s subject" it first converts the nifti file to the mgz format (orig.mgz, i think). In the proses the data appears to get converted to 8bit integers.

Starting with float data how does this impact the analysis? It seems to me that the range selected in "orig.mgz" is not optimal and this appears to be resampled in T1.mgz.

Are there ways to use a higher dynamic range, by forcing it to use floats or 16bit/32bit integers? Or should I just manually optimize/verify "orig.mgz" before running recon-all?

Also, are there ways to use the original resolution instead of resampling to 1mm iso?

Thanks!

Martijn