afni.nimh.nih.gov

Hi,
I am a little late, but you could try the 3dMVM_validator to test your model and GLTs and it will create the 3dMVM script for you.
So you don't have to worry about the extra spaces.
https://afni.nimh.nih.gov/pub/dist/doc/htmldoc/tutorials/3dMVM_validator/3dMVM_validator_overview.html

thanks, Justin