Rule of thumb for number of T1w images to make a template from in FSL VBM workflow?


Hello, I’m learning how to do VBM in FSL and was wondering is there a rule of thumb on how many images I need to select to make a template from?

I know already that it must be representative of the study subject population (i.e. if there are two groups with a 50-50 split, then there must be a 50-50 split in the images chosen for the template).

I have around a 100 subjects and only a PC of average power (Intel i5, 16GB RAM) to do all the processing on.